Let C[0, 1] have the inner product (f,g) = f(x)g(x)dx. For u = x and v= x + 1 find the following: a) ||f|| b) |lg|| c) (f,g) d) Find the angle between u and v.

Answers

Answer 1

The function v = x + 1, the norm is v = sqrt(integral of (x+1)^2 dx from 0 to 1), which evaluates to sqrt(5/3). The angle between u and v is arccos(1/√5).

a) The norm f of a function f in the vector space C[0, 1] with the given inner product is defined as the square root of the inner product of the function with itself. In this case, f = sqrt((f, f)) = sqrt(integral of f(x) * f(x) dx over the interval [0, 1]). For the function u = x, the norm is u = sqrt(integral of x^2 dx from 0 to 1), which evaluates to sqrt(1/3). For the function v = x + 1, the norm is v = sqrt(integral of (x+1)^2 dx from 0 to 1), which evaluates to sqrt(5/3).

b) The inner product space C[0, 1] induces a norm on the set of functions, and we can define the distance between two functions as the norm of their difference. In this case, the norm of the difference between the functions u and v is |u - v| = sqrt((u - v, u - v)) = sqrt(integral of (x - (x+1))^2 dx from 0 to 1), which simplifies to sqrt(1/3). Therefore, |u - v| = sqrt(1/3).

c) The inner product (f, g) between the functions f and g is defined as the integral of their pointwise product over the interval [0, 1]. For the functions u = x and v = x + 1, (u, v) = integral of (x * (x + 1)) dx from 0 to 1, which evaluates to 7/6.

d) The angle between two functions u and v in an inner product space can be computed using the definition of the inner product and the norms of the functions. The angle theta between u and v is given by the equation cos(theta) = (u, v) / (u * v). In this case, cos(theta) = (7/6) / (sqrt(1/3) * sqrt(5/3)), which simplifies to 1/√5. Therefore, the angle between u and v is arccos(1/√5).

Learn more about function here:

https://brainly.com/question/30721594

#SPJ11


Related Questions

Find the area under the standard normal distribution curve between z=0 and z=0.25. Use The Standard Normal Distribution Table and enter the answer to 4 decimal places.
The area between the two z values is ______

Answers

The area under the standard normal distribution curve between z=0 and z=0.25 is 0.0987.

First cumulative probability = z = 0 and

Second cumulative probability = z = 0.25

The Standard Normal Distribution Table, often known as the Z-table, may be used to determine the area under the standard normal distribution curve between z=0 and z=0.25. The table shows the total likelihood (area) up to a specified z-value. The cumulative probability, which can be found by looking up the z-value of 0 in the table, is 0.5000. The cumulative probability is 0.5987 when we look up the z-value of 0.25.

Calculating the area -

Area = First cumulative probability - Second cumulative probability

= 0.5987 - 0.5000

= 0.0987

Read more about distribution curve on:

https://brainly.com/question/30354210

#SPJ4

Can somebody help me please no links

Answers

Answer:

Lololololo9lolo9lkiujyhgdfbhjkifewkjuhgsdvcgfh

Step-by-step explanation:

Solve for v.
6v-7+2(5v+1) = -2(v + 4)

Answers

Answer:

v = -1/6

Step-by-step explanation:

Combine all like terms, getting 18v = -3. Then, divide both sides by 18 to get -3/18, or v = -1/6

Hopefully this helps- let me know if you have any questions!

y= 5x - 9; domain = { 1,3,7 }
what is the range values?

Answers

Answer:

Step-by-step explanation:

range = [-4,6,26]

Step-by-step explanation:

y = 5x - 9.....domain = [1,3,7]....the domain is ur x values, and I am assuming ur looking for the y values that go with the x ones

y = 5x - 9.....when ur domain (ur x) = 1

y = 5(1) - 9

y = 5 - 9

y = -4

y = 5x - 9...when ur domain (x) = 3

y = 5(3) - 9

y = 15 - 9

y = 6

y = 5x - 9...when ur domain(x) is 7

y = 5(7) - 9

y = 35 - 9

y = 26

so ur range (ur y valus) = [-4,6,26]

Joe has been riding his bicycle at a speed of 12 mph and has gone 48 miles. How long has he been riding?

Answers

Answer:

Joe's been riding 4 hours because if you divide 48 by 12 it gives you 4 and it's by hours so it would be 4 hours. point blank period.

Step-by-step explanation:

write a quadratic function with leading coefficient 1 that has roots ofp.

Answers

A quadratic function with leading coefficient 1 and roots of p can be expressed as f(x) = (x - p)(x - p), which simplifies to f(x) = x^2 - 2px + p^2.

To construct a quadratic function with leading coefficient 1 and roots of p, we utilize the relationship between the roots and the factors of a quadratic equation. Since p is a root, the factors of the quadratic function would be (x - p) and (x - p). By multiplying these factors together, we obtain the quadratic function f(x) = (x - p)(x - p). Simplifying further, we can expand the expression:

f(x) = (x - p)(x - p) = x^2 - px - px + p^2 = x^2 - 2px + p^2

Hence, the quadratic function with leading coefficient 1 and roots of p is given by f(x) = x^2 - 2px + p^2. This form allows for easy identification of the coefficients and reveals that the constant term of the quadratic is p^2.

For more information on quadratic function visit: brainly.com/question/14620824

#SPJ11

PLEASE HELP HARD FOR ME BUT EASY FOR OTHERS

Answers

The answer should be 72 degrees.
You add 31 and 39 first to get 70 degrees.
Then add 38 degrees because the angle in the lower corner is the same as one the would be placed to the right of the top two angles. 70 plus 38 equals 108 degrees.
Next you subtract 108 from 180 to get the answer for x. That gives you 73 degrees.

The curb weight of a new car is 3,347 pounds. How much does the car weigh?

Answers

Answer: 3,347 pounds

Step-by-step explanation:

Curb weight is simply the weight of a car with no passengers, cargo, or anyting other than the standard base model options.

Basically it's the weight of a base model car sitting on the dealership lot.  Curb weight would be different if ANYTHING is added to the base model car such as a passenger, any cargo, or any upgrades aftermarket or otherwise.

Answer:

Not sure if this the correct type of way your looking but its between 1 and 2 tons which is 1000

Step-by-step explanation:

I think...

Evaluate the integral by reversing the order of integration 7/2 cosx V1+cosx dc dụ.

Answers

The evaluated integral is (7/4) (π - (3√3)/6) (rounded to an appropriate decimal approximation based on the given values of π and √3).

To evaluate the integral ∫∫(7/2 cos(x)) dV, where the region of integration is given by V: 1 ≤ c ≤ 2 and 0 ≤ x ≤ cos⁻¹(2c-1), we can reverse the order of integration.

Step 1: Write the integral with reversed order of integration:

∫∫(7/2 cos(x)) dc dx

Step 2: Determine the limits of integration for the reversed order. The variable c now varies from 1 to 2, and x varies from 0 to cos⁻¹(2c-1). Therefore, the integral becomes:

∫[1,2] ∫[0,cos⁻¹(2c-1)] (7/2 cos(x)) dx dc

Step 3: Integrate with respect to x first. The integral with respect to x is straightforward:

∫[1,2] [sin(x)] [0,cos⁻¹(2c-1)] (7/2) dc

Step 4: Evaluate the inner integral:

∫[1,2] [sin(cos⁻¹(2c-1))] (7/2) dc

Step 5: Simplify the inner integral using the trigonometric identity sin(cos⁻¹(u)) = √(1 - u²):

∫[1,2] [√(1 - (2c-1)²)] (7/2) dc

Step 6: Integrate with respect to c:

(7/2) ∫[1,2] [√(1 - (2c-1)²)] dc

Step 7: Evaluate the integral:

Using the trigonometric substitution u = sin(t), du = cos(t) dt, and the limits change to t: π/6 ≤ t ≤ π/2.

(7/4) ∫[π/6, π/2] [√(1 - sin²(t))] cos(t) dt

Step 8: Simplify the integrand:

(7/4) ∫[π/6, π/2] [cos²(t)] dt

Step 9: Apply the double-angle formula for cosine:

(7/4) ∫[π/6, π/2] [(1 + cos(2t))/2] dt

Step 10: Split the integral into two separate integrals:

(7/4) [∫[π/6, π/2] (1/2) dt + ∫[π/6, π/2] (cos(2t)/2) dt]

Step 11: Integrate each term separately:

(7/4) [(t/2) + (sin(2t)/4)] evaluated from π/6 to π/2

Step 12: Substitute the limits and simplify:

(7/4) [((π/2)/2 + (sin(2(π/2))/4) - ((π/6)/2) - (sin(2(π/6))/4)]

Step 13: Simplify further:

(7/4) [(π/4 + 0 - π/12 - (1/4)(√3/2))]

Step 14: Simplify and calculate the final value:

(7/4) [(π/4 - π/12 - (√3/8))]

= (7/4) [(3π - π - 3√3)/12]

= (7/4) [(2π - 3√3)/12]

= (7/4) (π - (3√3)/6)

Learn more about the integral at

https://brainly.com/question/31059545

#SPJ4

Which of the following variables could theoretically be measured on a continuous scale? (a) Method of contraception used (b) length of time of residence in a state (c) task completion time (d) intelligence (e) authoritarianism (f) alienation (g) county of residence.

Answers

The variable that could theoretically be measured on a continuous scale is task completion time.

Task completion time is the duration between the initiation and completion of a specific task. It is continuous as it can take a large range of values on a continuous scale without any gap. It is frequently calculated in various businesses and researches to determine the efficiency and productivity of a particular task or process.

The other variables, such as method of contraception used, length of time of residence in a state, intelligence, authoritarianism, alienation, and county of residence, are all discrete variables. These variables take non-numerical values and are separate from each other by a gap.

These variables can be classified and counted into different categories, such as the number of individuals using a particular method of contraception, number of years of residence in a particular state, number of individuals belonging to a particular county, or number of individuals showing authoritarianism.

learn more about Task completion here:

https://brainly.com/question/3221895

#SPJ11

when comparing the f(x) = x2 2x and g(x) = log(2x 1), on which interval are both functions negative? (–[infinity], –2) (–2, 0) (–1, 1) (–[infinity], [infinity])

Answers

To find out on which interval are both functions f(x) = x^2 + 2x and g(x) = log (2x + 1) negative, we need to analyze the intervals of negative values of both functions.

We can plot their graphs to have a better understanding:

Graphs of f(x) = x² + 2x and g(x) = log(2x + 1)

Now, we need to observe the intervals where both functions lie below the x-axis: The function f(x) = x^2 + 2x is below the x-axis on the interval (-∞, -2).

The function g(x) = log(2x + 1) is below the x-axis on the interval (-1/2, 0).

Therefore, the interval on which both functions are negative is (-2, 0).Thus, the correct option is (–2, 0).

To know more about graphs refer to:

https://brainly.com/question/29129702

#SPJ11

PLSSS HELP IF YOU KNOW THISS:))

Answers

The answer is 428 there you go

Please help !!!!!!!!!

Answers

Answer:

5

Step-by-step explanation:

3x -12 = -36

-36 ÷ -3 = 12

-7 + 12 = 5

Answer:

The value of -7 + 3(-12) ÷ (-3) is 5

Step-by-step explanation:

First: -7 + -36 ÷ (-3)

Second: -7 + 12

Third: = 5

Therefore your value of this equation is 5.

your welcome.

hi amazing people please help i’ll give brainliest thanks!

Answers

Answer:

to present another's viewpoint

Answer:-

D, to analyze specific data i guess

Use the function f=d+1 to find the value of f when d=5.

Answers

Answer:

f = 6

Step-by-step explanation:

Plug in what you know then solve:

f = d + 1

f = 5 + 1

f = 6

The lenght of an arc in a circle with radius 8 inches is 3.2π. determine the measure of the arc​

Answers

Answer:

72

Step-by-step explanation:

32pi×360/2pi(8)=72

central angle= arc length 360/2pi×r

The measure of the arc is 72 degree

What is mean by Circle?

The circle is a closed two dimensional figure , in which the set of all points is equidistance from the center.

The measure of the arc, we use the formula:

⇒ Arc length = (angle measure / 360°) x 2πr

where r is the radius of the circle.

Now, We know that;

The radius is 8 inches, and that the arc length is 3.2π inches.

So, we can plug in those values and solve for the angle measure:

3.2π = (angle measure / 360°) x 2π(8)

3.2π = (angle measure / 360°) x 16π

Divide both sides by 16π:

0.2 = angle measure / 360°

Multiply both sides by 360°:

Angle measure = 72°

Thus, The measure of the arc is 72 degree

Learn more about the circle visit:

https://brainly.com/question/24810873

#SPJ2

g(x) = -3x-8g(x)=−3x−8g, left parenthesis, x, right parenthesis, equals, minus, 3, x, minus, 8
g\Big(g(g, left parenthesis
\Big)=10)=10

Answers

Answer:

try your best

Step-by-step explanation:

Im not sure how to do this can someone please help me only answer if you know

Answers

Answer:

57%

Step-by-step explanation:

FORMULA:LESS/TOTAL × 100%

=52/92 × 100%

=56.52 %

ROUND OFF TO NEAREST WHOLE NUMBER

56.52%=57%

(because the 5 after the (.) is near 1)

f(x) = 9x-7. If f(x)= -7, find x.​

Answers

Answer: the answer is 56

Step-by-step explanation: since the f(x) is -7 it would be 9 times -7 then minus 7 and get the answer.

Veterinarians often use nonsteroidal anti-inflammatory drugs (NSAIDs) to treat lameness in horses. A group of veterinary researchers wanted to find out how widespread the price is in the United States. They obtained a list of all veterinarians treating large animals, including horses. They send questionnaires to all the veterinarians on the list. Such a survey is called a cemus. The response rate was 40%. What is the population of interest? a all veterinarians Oball veterinarians treating large animals e all veterinarians in the United States treating large animals, including horses d. All of the answer options are correct.

Answers

The population of interest in this case is (d) All of the answer options are correct. It includes all veterinarians, all veterinarians treating large animals, and all veterinarians in the United States treating large animals, including horses.

The population of interest in this study is defined as all veterinarians in the United States who treat large animals, including horses. This population includes all individuals who fit this criteria, regardless of their location or any other specific characteristics.

The researchers wanted to gather information about the prevalence of using nonsteroidal anti-inflammatory drugs (NSAIDs) for treating lameness in horses among veterinarians in the United States. To do this, they obtained a list of all veterinarians who treat large animals, including horses, and sent questionnaires to each of them.

The response rate refers to the percentage of veterinarians who completed and returned the questionnaires out of the total number of questionnaires sent. In this case, the response rate was 40%, meaning that 40% of the veterinarians who received the questionnaires responded to them.

By surveying a representative sample of veterinarians, the researchers can gather information and make inferences about the larger population of veterinarians in the United States who treat large animals, including horses. The data collected from the survey can provide insights into the widespread use of NSAIDs for treating lameness in horses and contribute to the overall understanding of veterinary practices in this context.

To learn more about veterinarians

https://brainly.com/question/13901180

#SPJ11

X^2-18x-2=0. Which number would have to be added to “complete the square”?

Answers

Step-by-step explanation:

its83

(a+b)^2=a^2+2ab+b^2

x^2+(-9)2x-2=0

b^2=81

83+(-2)=81

Eugenia gasto 10 euros en el quiosco, compro 5 bocaditos, un paquete de galletas que costaba 1 euro y pagó 4 euros que debia ¿cuanto cuesta cada bocadito?

Answers

Answer:

the each snack cost is 1

Step-by-step explanation:

Let us assume the each snack cost be x

So according to the question

The following equation would be applied

5x + 1 + 4 = 10

5x + 5 = 10

5x = 5

x = 1

hence, the each snack cost is 1

So the same would be considered and relevant too

In a study of spat dating es were asked them in the same time to What other out of the popu 23,50710090 What is the concerto? D-lichte places need was the other the contacto OA TN repostane posting tone OR Weather to the memo and on dem O. We second have the end மொயமால மாமா mg 140 Newt 0 View an example Get more help Help me solve this C M a o 0 10 1 In a study of speed dating male subjects were asked to rate the attractiveness of their female dates, and a sample of the results is listed below (1 = not attractivo 10 = extremely attractive) Construct a confidence interval using a 95% confidence level What do the results tell about the mean attractiveness ratings of the population of all adult females? 6,9,3,9, 6, 6, 8, 8, 7, 10,5,9 What is the confidence interval for the population mean? [<<(Round to one decimal place as needed) west point(s) possible in a study of speed dating, male subjects were asked to rate the attractiveness of their female dates, and a sample of the results is listed below (1 = not attractive 10 = extremely attractive) Construct a confidence interval using a 95% confidence level What do the results tell about the mean attractiveness ratings of the population of all adult females? 6,9,3,9,6,6,8,8.7. 10,5,9 PO What is the confidence interval for the population mean? <-- (Round to one decimal place as needed) What does the confidence interval tell about the population of all adult fernales? Select the correct choice below and, if necessary, fill in the answer box(es) to complete your choice. ative Area from the LEF 02 O A. The results tell nothing about the population of all adult females, because participants in speed dating are not a representative sample of the population of all adult females 5000 5178 03 5120 5517 5990 5871

Answers

Confidence interval are 5.9 < μ < 8.5 for the population mean.

Given:

Let x = 6,9,3,9, 6, 6, 8, 8, 7, 10,5,9

N = 12, ∑x = 86 x = 86/12 = 7.16

[tex]s=\sqrt{\frac{(x-\bar x)^2}{N-1} } = \sqrt{\frac{(6-7.16)^2+.....+(9-7.16)}{12-1} }[/tex]

[tex]\sqrt{\frac{45.66}{11} } =2.03[/tex]

At 98% confidence interval.

[tex]z=1-\frac{95}{100} =0.05\\[/tex]

[tex]t=2.201[/tex]

Confidence interval.

[tex]\bar x \pm t\frac{s}{\sqrt{n} } = 7.16\pm 2.201(\frac{2.03}{\sqrt{12} } )[/tex]

[tex]5.9 < \mu < 8.5[/tex]

Therefore, 95% confidence interval are 5.9 < μ < 8.5

Learn more about confidence interval here:

https://brainly.com/question/32279456

#SPJ4

pls help i’ll give brainliest

Answers

Answer:

1/5x12 and 12/5

Step-by-step explanation:

both are dividing by five or equal to 2.4 which is the same as 1/5 of 12

Answer Of means to multiply so two correct answer would be B,D  

Step-by-step explanation: hope this helps :)

can some one please help. 4789658953 round to the nearest 10th
mean =
mean absolute deviation =

Answers

Answer:

i believe your answer is.

4,789,658,950

Step-by-step explanation:

e. 15 = 1.5t t=? Solve please

Answers

Answer:

E Z

10

Step-by-step explanation:

15 = 1.5t

so t = 15/1.5

      = 10

Answer: t = 10

1. Switch sides

- 1.5t = 15

2. Multiply both sides by 10

- 15t = 150

3. Divide both sides by 15

4. Simplify

t = 10


Please please help I swear I will give you brainlist if it’s right and please explain for part a and part b thank you

Answers

Answer:

A. Reduction

B. 2

Step-by-step explanation:

A: A reduction is when the image is getting smaller. The apostrophes show the new, or second, image. It is called "prime." Because the prime is smaller than the original, it is a reduction.

B: Scale factor is when you divide, which number changes it. In other words, the image moved from 4 to 2, from 2 to 1, etc, which means we are DIVIDING by 2.

Suppose X is an exponential random variable, show that E(X²) = 2/λ²

Answers

The exponential distribution is a continuous probability distribution that is widely used in probability theory and statistics. In probability theory, an exponential random variable is a continuous random variable that represents the waiting time between events in a Poisson process.

Suppose X is an exponential random variable. We have to show that E(X²) = 2/λ². We can show this by using the definition of expectation that is, E(X) = ∫[0,∞] xf(x) dx

where f(x) is the probability density function of X.

Similarly, E(X²) = ∫[0,∞] x²f(x) dx

We know that the probability density function of an exponential distribution with parameter λ is given by f(x) = λe^(-λx)So, E(X²) = ∫[0,∞] x²λe^(-λx) dx

Using integration by parts, we have ∫[0,∞] x²λe^(-λx) dx= [-x²e^(-λx)/λ] + [2xe^(-λx)/λ²] + [(-2/λ³)e^(-λx)]∞ 0= (2/λ²)

E(X²) = 2/λ².

The exponential distribution is a continuous probability distribution that is widely used in probability theory and statistics. In probability theory, an exponential random variable is a continuous random variable that represents the waiting time between events in a Poisson process.

Suppose X is an exponential random variable. We have to show that E(X²) = 2/λ². We can show this by using the definition of expectation that is, E(X) = ∫[0,∞] xf(x) dx

where f(x) is the probability density function of X.

Similarly, E(X²) = ∫[0,∞] x²f(x) dx

We know that the probability density function of an exponential distribution with parameter λ is given by f(x) = λe^(-λx)So, E(X²) = ∫[0,∞] x²λe^(-λx) dx

Using integration by parts, we have ∫[0,∞] x²λe^(-λx) dx= [-x²e^(-λx)/λ] + [2xe^(-λx)/λ²] + [(-2/λ³)e^(-λx)]∞ 0= (2/λ²)Therefore, the main answer to this question is E(X²) = 2/λ².

Learn more about probability theory: https://brainly.com/question/31469353

#SPJ11

Someone help what would my average be if I got 100% on my both of my tests? I just wanna know

Answers

Answer:

To figure out your average, you add them together then divide by2

Step-by-step explanation:

Which of the following statements best describes the value of the expression 6x + 7 when x = 5?

Answers

Answer:

? is there a option?

Step-by-step explanation:

Answer:

37

Step-by-step explanation:

6x+7

6(5)+7

37

Other Questions
Which of these compounds are molecular?CBr4FeSP4O6PbF2 ando Company incurs a $10.00 per unit cost for Product A, which it currently manufactures and sells for $13.50 per unit. Instead of manufacturing and selling this product, the company can purchase it for $5.00 per unit and sell it for $11.90 per unit. If it does so, unit sales would remain unchanged and $5.00 of the $10.00 per unit costs of Product A would be eliminated. 1. Prepare Incremental cost analysis. Should the company continue to manufacture Product A or purchase it for resale Outline what other countries have done to address womenrepresentation at the C-suite and Board level and assess theeffectiveness of such measures adopted by other countries (+6) (+2) =answer choices +12 +8+4+3-3 "Which of the following is true? Airfreight A. has lower transporting rates than trucks. B. efficiently delivers all types of goods. C. serves many more locations than trucks. D. is best for goods that are heavy relative to their sales value, such as iron ore. E. can help reduce inventory costs." What was kesz organization about?Read 180 Mr. Simpson has 5 boxes of paintbrushes in his art room. After the first week of school, he buys 3 more paintbrushes. The expression below shows the total number of paintbrushes in Mr. Simpson's art room when prepresents the number of brushes in each box. 3 + px 5 If each box contains 8 paintbrushes, how many total paintbrushes are in Mr. Simpson's art room? (Show your work or explain how you got your answer in words) help pls and tyyy:))) allocate the joint cost to l-ten, triol, and pioze using the constant gross margin percentage method. round the gross margin persentage to four decimal places and round all other computations to the nearest dollar.joint costproduct allocationL-ten ______Triol ______Pioze ______total ______ What is another way to express 52 + 24?8 (6 + 3)4(13+6)6 (9+4)13 (4+2)Done An ecosystem with great biologicaldiversity decreases F the number of species present inthe ecosystemG competition between differentspecies in the ecosystemHavailable space for organisms inthe ecosystemJ available food supply fororganisms in the ecosystem I have been a high school teacher for 25 years and there is only 1 pencil I trust to get the job done and that is Stagecoach. Its lead is 99.9% safe. So mothers, no need to worry about those younger students getting lead poison. Its safe for them as well. So get the pencils teachers love! Stagecoach Pencils, teacher trusted and mother approved. This ad is an example of PathosLogosEthosAll of the above Shade 3/4 on the grid explain the word Detective and Prosecutor.i will mark brainliest How does the geographic theme of place help us understand life on Earth?O A. It tells us what a region is like.B. It tells us where a region is located.C. It tells us about people's migration to a region.D. It tells us how people have affected the environment of a region. Don't know why we couldn't have gone swimming this afternoon. Is it grammatically correct sentence? A your 22 A young management trainee in the pharmaceutical sector was frustrated when he found that his boss would not let him embark on a critical project execution related to development of a vaccine until he had a proper plan, even though creating the execution plan would entail some initial delay. How can you justify the action of his boss? Some project managers prefer the PERT chart over the Gantt chart because it clearly illustrates task dependencies. A PERT chart, however, can be much more difficult to interpret, especially on complex projects. Alternatively, some project managers may choose to use both techniques. If you are the project manager of a residential construction project, will you prefer PERT chart to Gantt chart? Explain why? Hey I'm back anyone remembers me? How does having eyes in front help predators hunt their prey?