Suppose that a, b, x and y are real numbers such that ax+by = 1, ax² + by² = 11, ax³ + by³ = 25 and ax⁴ + by⁴ = 83. Find the value of ax⁵ + by⁵.​

Answers

Answer 1

Answer:

[tex]ax^5+ by^5=241[/tex]

Step-by-step explanation:

Given:

[tex]ax + by = 1[/tex][tex]ax^2+ by^2 = 11[/tex][tex]ax^3+ by^3 = 25[/tex][tex]ax^4+ by^4 = 83[/tex]

We can re-write the left sides of the given equations as follows:

[tex]ax^2+ by^2=(ax+by)(x+y)-xy(a+b)[/tex]

[tex]ax^3+ by^3=(ax^2+by^2)(x+y)-xy(ax+by)[/tex]

[tex]ax^4+ by^4=(ax^3+by^3)(x+y)-xy(ax^2+by^2)[/tex]

Therefore, following this pattern:

[tex]ax^5+ by^5=(ax^4+by^4)(x+y)-xy(ax^3+by^3)[/tex]

Use the given values and the expanded expressions to create 2 equations to help find the values of (x+y) and xy:

Equation 1

[tex]ax^3+ by^3=(ax^2+by^2)(x+y)-xy(ax+by)[/tex]

[tex]\implies 25=11(x+y)-xy(1)[/tex]

[tex]\implies 25=11(x+y)-xy[/tex]

Equation 2

[tex]ax^4+ by^4=(ax^3+by^3)(x+y)-xy(ax^2+by^2)[/tex]

[tex]\implies 83=25(x+y)-xy(11)[/tex]

[tex]\implies 83=25(x+y)-11xy[/tex]

Multiply Equation 1 by 11:

[tex]\implies 275=121(x+y)-11xy[/tex]

Then subtract Equation 2 from this to eliminate 11xy and find the value of (x+y):

[tex]\implies 192=96(x+y)[/tex]

[tex]\implies (x+y)=2[/tex]

Multiply Equation 1 by 25:

[tex]\implies 625=275(x+y)-25xy[/tex]

Multiply Equation 2 by 11:

[tex]\implies 913=275(x+y)-121xy[/tex]

Subtract the 2nd from the 1st to eliminate 275(x+y) and find the value of xy:

[tex]\implies 288=-96xy[/tex]

[tex]\implies xy=-3[/tex]

Therefore, we now have:

[tex]ax^4+ by^4 = 83[/tex][tex]ax^3+ by^3 = 25[/tex][tex](x+y)=2[/tex][tex]xy=-3[/tex]

Substitute these into the equation for ax⁵ + by⁵ and solve:

[tex]\implies ax^5+ by^5=(ax^4+by^4)(x+y)-xy(ax^3+by^3)[/tex]

[tex]\implies ax^5+ by^5=(83)(2)-(-3)(25)[/tex]

[tex]\implies ax^5+ by^5=166+75[/tex]

[tex]\implies ax^5+ by^5=241[/tex]


Related Questions

Yuson must complete 15 hours of community sevice. She does 3 hours each day. Which linear equation represents the hours Yuson still has to work after x days?

A. Y=3x + 15
B. Y= -3x - 15
C. Y= -3x + 15
D. Y= 3x - 15

Answers

Answer:

C)   y = -3x + 15

Step-by-step explanation:

Let's start with the hours required, 15.  For each day worked we can subtract 3 hours.  X days would mean 3x hours.  Subtract that from the goal of 15 hours:

15 - 3x

The time remaining, y, is given by the equation 15 - 3x.

Rearrange the equation to match the format in the options,

y = 15 - 3x

y = -3x + 15

Option C

This table shows input and output values for a linear function f(x)
What is the difference of outputs for any two inputs that are three values apart.
Express your answer as a decimal.​

Answers

The answer is 0.75 because I took the test and that's what the answer was :)

14 friends go out for dinner and the bill for food and drink comes to £130. The friends decided to add a 5% tip on the top of this total. If they divide this expense equally between them, How much does each friend pay?

Answers

The amount each friend does pay is £9.75

How to calculate the pay of each friend using fractions and arithmetic operations?

We are going to find 5% of the total amount paid and divide it by the numbers of all the friends to determine the amount paid by each one of them.

From the given information:

The 5% of 130 = £6.5Total amount paid = £130 + £6.5 = £136.5

Therefore, the cost of each friend is = [tex]\dfrac{136.5}{14}[/tex]

The cost of each friend = £9.75


Learn more about fractions here:

https://brainly.com/question/78672

#SPJ1

Q: Sam challenges Tom to a race. If Sam can run 6 meters per second and Tom can run at 7 meters per
second. After a minute and a half how far apart will they be?

Answers

Answer:

90 meters

Step-by-step explanation:

so, what we know is that there are  90 seconds in one minute and a half.

Sam can run 6 meters per second. which means after 90 seconds, he should have run 540 meters.

Tom can run 7 meters per second. This means after 90 seconds, he should have run 630 meters.

630-540 = 90

give brainliest please!

hope this helps :)


Evaluate 5(x - 1) - 2 when x = 3

Answers

Answer:

8

Step-by-step explanation:

Given algebraic expression:

5(x - 1) - 2

To:

Evaluate this expression using x = 3

Solution:

5(x - 1) - 2

Evaluate by plugging x = 3 to this expression:

5(3-1)-2

Simplify using PEMDAS.

5(2)-210-28

We can conclude:

By evaluating x = 3 to the given expression,the answer will be 8.

Solve for x in the equation x squared 4 x minus 4 = 8.

Answers

Answer:

±2√3

Step-by-step explanation:

Equation :

x² -4 = 8

x² -12 = 0

Using the quadratic formula then simplifying gives you :

±2√3

I know this lacks explanation but please brainliest

Answer:

x=2 or -6

Step-by-step explanation:

×^2+4×-4=8

8 will enter inside and become -8

x^2+4x-4-8=0

x^2+4x-12

(x^2+6x)(-2x-12)

x(x+6)-2(x+6)

(x-2)(x+6)

x=2 or x=-6

The base of a triangular prism is a right triangle with a base of 6 inches, a height of 8 inches, and a third side length of 10 inches. the height of the prism is 14 inches. find the surface area of the prism.

Answers

The surface area of the rectangular prism with the dimensions that are stated is: 384 in.²

What is the Surface Area of a Triangular Prism?

Surface area = perimeter of base × height of prism + 2(base area)

= (s1 + s2 + s3)L + 2(1/2bh)

Given the following:

side of base (s1) = 6 in.side of base (s2) = 8 in.side of base (s3) = 10 in.Length of prism (L) = 14 in.Triangular base length (b) = 6 in.h = 8 in.

Surface area = (6 + 8 + 10)14 + 2(1/2 × 6 × 8)

Surface area = 384 in.²

Learn more about the surface area of a rectangular prism on:

https://brainly.com/question/1310421

#SPJ4

I need help
30 POINTS!!!!

Answers

Answer:

A. Upward

B. (-2, -1)

C. X= -3, -1 ||| Y= 3

D. X=-2

Step-by-step explanation:

A flower pot hangs from a brace. △MNQ and △MNP form the brace what is the value of x?

Answers

The value of x from the given triangle formed by the pot hanging from a brace is; x = 50°

How to find the missing angle in a triangle?

We are given from the diagram that;

∠NMP = 110° and ∠NPM = 30°

Sum of angles in a triangle is 180°.

Thus;

∠MNP = 180 - (110 + 30)

∠MNP = 40°

Thus;

x = 90 - 40

x = 50°

Read more about angles in a triangle at: https://brainly.com/question/7620723

#SPJ1

PLEASE HELP ASAP

What is the missing statement for the sixth step in the proof below?

Answers

Answer:

C

Step-by-step explanation:

The last reasoning is the side angle side theorem. In the whole proof, there is no mention of an angle. So the answer has to involve prooving that the angle in between the two sides that have been proven similar is the same in both traingles. This is best accomplished by statement C.

True or False?
A square can be similar to a triangle since a square is composed of two triangles.
When Ronald goes to BIG Burgers, he orders a sandwich and a side order. For the

Answers

Answer:

true is the answer not hard question


The following cone has a height of 12 cm and a slant height of 16 cm. A right angle is formed between the height and radius of the cone
what is the length of the radius

Answers

Step-by-step explanation:

[tex]\pink{\large{\underline{\underline{\sf Given:-}}}}[/tex]

[tex] \sf Height_{\blue{cone}}=12 \: cm [/tex][tex] \sf Slant \: height_{\blue{cone}}=16\: cm [/tex]

[tex]\pink{\large{\underline{\underline{\sf To \: find:-}}}}[/tex]

[tex] \sf Radius_{\blue{cone}}=? [/tex]

[tex]\pink{\large{\underline{\underline{\sf Solution:-}}}}[/tex]

We know that,

[tex]\underline{\boxed{\sf (Radius)^2= (Slant height)^2-(height)^2}}[/tex]

[tex] \sf (Radius)^2 = (16)^2-(12)^2[/tex]

[tex] \sf (Radius)^2 = 256-144=112[/tex]

[tex] \longmapsto \sf Radius = \sqrt{112}≈10.6\:cm[/tex]

One day Maria spends 6/20 of the day asleep. Calculate in hours and minutes the amount of time she spends asleep.

Answers

Answer:

7 hours and 12 minutes

Step-by-step explanation:

there are 24 hours in a day, so multiply 6/20 by 24 to find the number of hours:

6*24/20 = 36/5 = 7  1/5 hours

we now know maria sleeps for 7 whole hours

next, there are 60 minutes in an hour, so multiply 1/5 by 60 to get 12 minutes

the perimeter of a rectangle is 20 cm and it's area is 24cm^2 find the length and breath of the rectangle​

Answers

Answer:

length = 6cm , breadth = 4cm

Step-by-step explanation:

Let's assume length = l

breadth = b

Given perimeter of a rectangle = 20 cm

2(l+b) = 20

l+b = 20/2

l+b = 10

l = 10 - b____(1)

Given area of rectangle = 24 cm²

l×b = 24____(2)

(1) in (2) => l × b = 24

(10-b) × b = 24

10b - b² = 24

10b = 24 + b²

0 = b² - 10b + 24

b² - 10b + 24 = 0

b² + 6b + 4b + 24 = 0

b(b+6) +4(b+6) = 0

(b+4)(b+6) = 0

b+4 = 0. &. b+6 = 0

b = -4. b = -6

breadth must be less than length and it should be positive

So b = 4 cm

b=4 in (1)

(1)=> l = 10 - b

l = 10 - 4

l = 6

True or false? The graph represents a function

Answers

Answer:

true

Step-by-step explanation:

The statement is true because every graph associated a unique x-value for each y - value

Calculate the area of the following composite figure. (Please i need help with this)

Answers

The area of the composite shape in the diagram given is: 100 square inches.

How to Find the Area of a Composite Figure?

Area of a composite figure = sum of the areas of the shapes that make up the figure.

Area of the composite shape = 2(area of triangle) = 2(1/2bh)

Area of the composite shape = 2(1/2×10×10)

Area of the composite shape = 100 square inches.

Learn more about the area of a composite shape on:

https://brainly.com/question/8408690

#SPJ1

If f (x) = StartRoot one-half x minus 10 EndRoot + 3, which inequality can be used to find the domain of f(x)?
StartRoot one-half x EndRoot greater-than-or-equal-to 0
One-half x greater-than-or-equal-to 0
One-half x minus 10 greater-than-or-equal-to 0
StartRoot one-half x minus 10 EndRoot + 3 greater-than-or-equal-to 0

Answers

The inequality that represents the domain of the function is [tex]\frac 12x - 10 \ge 0[/tex]

How to determine the domain?

The function is given as:

[tex]f(x) = \sqrt{\frac 12x - 10} + 3[/tex]

Set the radicand greater than or equal to 0

[tex]\frac 12x - 10 \ge 0[/tex]

Multiply through by 2

x - 20 ≥ 0

Add 20 to both sides

x ≥ 20  

Hence, the domain of the function is x ≥ 20  

Read more about domain at:

https://brainly.com/question/1770447

#SPJ1

A lake near the Arctic Circle is covered by a thick sheet of ice during the cold winter months. When spring arrives, the warm air gradually melts the ice, causing its thickness to decrease at a rate of 0.2 meters per week. After 7 weeks, the sheet is only 2.4 meters thick.
Let y represent the ice sheet's thickness (in meters) after x weeks.

Complete the equation for the relationship between the thickness and number of weeks.
y=_____

Answers

The equation for the relationship between the thickness and number of weeks is y = 3.8 - 0.2x

How to write equation?

Ice lost per week = 0.2 metersIce remaining after 7 weeks = 2.4 metersNumber of weeks = xRelationship between the thickness and number of weeks = y

Ice lost at 7 weeks = 7(0.2) = 1.4 meters

Total thickness of ice before loss = Ice remaining after 7 weeks + Ice lost at 7 weeks

= 2.4 + 1.4

= 3.8 meters

The equation:

y = Total thickness of ice before loss - (Ice lost per week × Number of weeks)

= 3.8 - (0.2 × x)

y = 3.8 - 0.2x

Learn more about equation:

https://brainly.com/question/8284719

#SPJ1

If y=2x-1 is changed to y = x+ 2,
how would the graph of the new
function compare with the first one in terms of steepness and shift?

Answers

The graph of the function y = x+2 is steeper than the graph y = 2x-1.

What is a graph?

A graph is the representation of the data on the vertical and horizontal coordinates so we can see the trend of the data.

Given functions are:-

y=2x-1y = x+2

The graph of the functions is attached with the answer below. In the graph, we can see that the slope of the graph y = x+2 is steeper than the graph of y = 2x - 1.

The two graphs intersect at the point ( 3,5 ) so it is the solution of the two linear equations.

Hence the graph of the function y = x+2 is steeper than the graph y = 2x-1.

To know more about graphs follow

https://brainly.com/question/25020119

#SPJ1

help please and I'll mark you brainiest.​

Answers

The probability will include:

P(A and 1) = 1/24P(C and 2) = 1/12.P(B and 3) = 1/12.P(A and 4) = 1/12

How to calculate the probability?

The probability of P(A and 1) will be:

= 1/4 × 1/6

= 1/24

The probability of P(C and 2) will be:

= 1/4 × 2/6

= 1/12

The probability of P(B and 3) will be:

= 2/4 × 1/6

= 1/12

The probability of P(A and 4) will be:

= 1/4 × 2/6

= 1/12

Learn more about probability on:

brainly.com/question/24756209

#SPJ1

A population of beavers decreases exponentially at a rate of 7.5% per year. What is the equivalent monthly rate to the nearest hundredth of a percent

Answers

Answer:

0.65%

Step-by-step explanation:

i took the test

What is the x and y intercept of y=1/3x-2, y=12-6x, and y=3x-7? Please show work!

Answers

Answer:

y = 1/3x - 2:

y - intercept: - 2x - intercept: 6

y = 12 - 6x:

y - intercept: 12x - intercept: 2

y = 3x - 7:

y - intercept: -7x - intercept: 7/3

Step-by-step explanation:

Hello!

Slope Intercept Form

The slope-intercept form of a line is [tex]y = mx + b[/tex]

y = output, ordinatem = slopex = input, abscissab = y-intercept

y = 1/3x - 2

The y-intercept is the "b" value of the line, given as -2.

To find the x-intercept, we simply replace the y-value with 0:

0 = 1/3x - 22 = 1/3x6 = x

y - intercept: - 2

x - intercept: 6

____________________________________________________

y = 12 - 6x

You can rearrange the equation, y = -6x + 12, to find the y-intercept: 12.

Solving for the x-intercept (remember, replace y with 0):

0 = -6x + 12-12 = -6x2 = x

y - intercept: 12

x - intercept: 2

____________________________________________________

y = 3x - 7

Simply take the "b" value, -7, to find the y-intercept of -7.

Solve for the x-intercept:

0 = 3x - 77 = 3xx = 7/3

y - intercept: -7

x - intercept: 7/3

Additional Note:

You can also solve for the y-intercept by replacing x with 0. This method can be used for any interests, just plug in the opposite variable from what you are solving for with 0.

The proof is that the x-intercept is the value when the y = 0, the x-axis. You can plug in 0 for y to solve for x. Similarly, when solving for the y-intercept, you plug 0 for x as the y-axis is at x = 0.

Please help! Giving brainlist!

Answers


The slope is 5/2


The slope formula is:

m = y2 - y1 / x2 - x1


Our points are:

(-1, 4) and (1, 9)


Just insert them into the formula and simplify to get your answer:


m = 9 - 4 / 1 + 1

m = 5/2

Solve for x

−5(-3x-3)+5x+4=-1

Answers

Simple and best practice solution for -5(-3x-3)+5x+4=-1 equation. Check how easy it is, and learn it for the future. Our solution is simple, and easy to understand, so don`t hesitate to use it as a solution of your homework.

Solve for x−5(-3x-3)+5x+4=-1Solution for -5(-3x-3)+5x+4=-1 equation:-5(-3x-3)+5x+4=-1We move all terms to the left:-5(-3x-3)+5x+4-(-1)=0We add all the numbers together, and all the variables5x-5(-3x-3)+5=0We multiply parentheses5x+15x+15+5=0We add all the numbers together, and all the variables20x+20=0We move all terms containing x to the left, all other terms to the right20x=-20x=-20/20x=-1 See similar equations:| 2x+5=0.5(4x+10) | | x+(x-11)=43 | | 39-v=56 | | 3x-4x+8=-5x+4x-9 | | -3+8u=5(u- | | -4(-2x-2)+x-2=?48 | | 2x+10=+2x+10 | | 13=-3a-5 | | 7y=64-y | | w-5/7=72/3 | | 58y+7=34y?3 | | -36=4(v-5)-6v | | 3x-4-5x=x=4=x | | ?4(r+2)=4(2?2r) | | y/2=22 | | 6x+12-x=x+8 | | -3/8y=0 | | 7(2=-x)=3(x+2) | | x-x=234 | | 0=(2x-4)(x+6) | | -8x+-7=-15 | | 16x-x=100 | | 5k+21=17k=-3 | | 14x-x=37 | | 1-4x-8=8 | | w-33=12 | | (13x+20)=(7x+38) | | -3(2b+-5)=3b | | 30x-x=473 | | 13x-10=6x+4 | | y=-2,y=-16/8 | | (17.155)^2=(0)^2+2a(-15) |

#keeponlearning

Which list correctly orders A, B, and C from least to greatest when A=171, B = -6, and C=1-51?
A, B, C
B, C, A
C, B, A
A, C, B

Answers

The 3rd option is correct

Find the area and volume of a 11 inch cube (pls write do the equation in steps)

Answers

Answer:

1331 inches cubed

Step-by-step explanation:

V=LHW

since it is a cube, the length, height, and width will all be the same; 11 inches. You have to multiply 11 by 11 by 11, which equals 1331.

Hope this helped!

Please help and thanks
Choose the correct answer
2x>12x and 7x<14

Answers

Answer:

C - x < -6 and x < 2

Step-by-step explanation:

2x ">" -12 and 7x < 14. with negative numbers, the bigger the number the less it is. -12 < -6 because negative numbers work the opposite way that positive numbers do. I hope this helps you!!!!

the ratio of Â, B and C in triangle ABC is 2:3:4. calculate the size of each angle​

Answers

Answer:

40°, 60°, 80°

Step-by-step explanation:

sum the parts of the ratio , 2 + 3 + 4 = 9 parts

the sum of the 3 angles in a triangle = 180° , then

180° ÷ 9 = 20° ← value of 1 part of the ratio , then

2 parts = 2 × 20° - 40° = ∠ A

3 parts = 3 × 20° = 60° = ∠ B

4 parts = 4 × 20° = 80° = ∠ C

Explain step by step how you find the product of 6x^2y^5 and 3x^2 - 8x + 2xy^2 + 4y^3

Answers

The final product is 18x⁴y⁵ - 48x²y⁵+12x³y⁷+24x²y⁸

What is a product ?

The product is result obtained when a number or an expression is multiplied by the other number.

The product of the given expression

6x²y⁵ and 3x²-8x+2xy²+4y³

6x²y⁵ (3x²-8x+2xy²+4y³)

Step 1 : To multiply each term in the bracket with the other expression

out of the bracket

6*3*x²*y⁵*x² - 6*8*x²*y⁵ +6x²y⁵ *2*x*y² + 6*4*x²y⁵ *y³

Step 2 : The like variables will be solved

18x⁴y⁵ - 48x²y⁵+12x³y⁷+24x²y⁸

This is the final product

To know more about the product

https://brainly.com/question/17765678

#SPJ1

Write the equation of the line that passes through the points (-3,3) and (4, -1).
put your answer in fully reduced point-slope form, unless it is a vertical or horizontal
line,

Answers

[tex](\stackrel{x_1}{-3}~,~\stackrel{y_1}{3})\qquad (\stackrel{x_2}{4}~,~\stackrel{y_2}{-1}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{-1}-\stackrel{y1}{3}}}{\underset{run} {\underset{x_2}{4}-\underset{x_1}{(-3)}}} \implies \cfrac{-4}{4 +3} \implies \cfrac{ -4 }{ 7 }[/tex]

[tex]\begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{3}=\stackrel{m}{-\cfrac{4}{7}}(x-\stackrel{x_1}{(-3)})\implies y-3=-\cfrac{4}{7}(x+3)[/tex]

Other Questions
What would you do if when you ok so he said yes would go The tables show linear functions representing the cost for purchasing different amounts of broccoli and cauliflower. which function has the greater slope and what does it indicate? the broccoli function has the greater slope, which shows that the cost per pound of broccoli is less than the cost per pound of cauliflower. the broccoli function has the greater slope, which shows that the cost per pound of broccoli is greater than the cost per pound of cauliflower. the cauliflower function has the greater slope, which shows that the cost per pound of cauliflower is less than the cost per pound of broccoli. the cauliflower function has the greater slope, which shows that the cost per pound of cauliflower is greater than the cost per pound of broccoli. What must happen for carbon dioxide to sublimate at a given pressure ? Where should a response-to-literature essay identify the author and title of the literary work being discussed? What are some environmental advantages of building green? a company sold a machine for 15,000$ in cash. The machine originally cost $38,000 and accumulated depreciation was 20,000 How does the Bill of Rights provide continuity?It is clear in giving the federal government the right to act more favorable to certain religions.It is accepted by all people and allows individual states to determine the extent of an individual's freedom of speech.It is never challenged by the Supreme Court, so the meanings of those rights never changes.It remains the heart of individual liberty, rule of law, and limited government in the United States. part 3 to the please help question sorry im asking so many questions 9.) List three things vertical and horizontal lines have in common. Using a straightedge and compass the ancient Greeks were able to construct many geometric objects Find the volume of the prism. 9km 8km 6km In order to become a government official during the Song Dynasty, a person had to pass a mathematics & economics exam. true or false { 99 points} i need help with this assignment i'm failing eng. i have a lot more assignments to do so could anyone please help if the file is blank ask me about the question do not answer the question at the very bottom Please help, its urgent. (Question Below) Select the correct answer from each drop-down menu. Amy put some salt in a weighing dish. Then she put the weighing dish on a sensitive balance to measure the mass of the salt. She removed the weighing dish from the balance and put it in several similar balances. She recorded the mass each time. Mass 1 Mass 2 Mass 3 Mass 4 Mass 5 5.608 g 5.607 g 5.608 g 5.608 g 5.609 g Amy forgot to subtract the mass of the empty weighing dish from her measurements, and she reported the mass of the salt as 5.608 grams. Amy's measurement of the salt's mass(1)______ accurate because(2)______ . Amy's measurement of the salt's mass(3)_____precise because(4) _______ .1. A. is B. is not2. it is not close to the actual valueshe used five different balancesthe individual measurements are similar3. isis not4. it is not close to the actual valueshe used five different balancesthe individual measurements are similar What's manifestation Submitting a BidYou want to bid on a project for the pool shown. The project involves ordering and installing the brown tile that borders the pool, and ordering a custom-made tarp to cover the surface of the pool. In the gure, each grid square represents 1 square foot. You pay $5 per linear foot for the tile.You pay $4 per square foot for the tarp It takes about 15 min to install each foot of the tileA) estimate the total cost for the tile and the tarp Respiration in Organisms:- Visit the doctor. Learn about the various diseases related to respiratory system. What are the measures that may be taken to prevent them? Prepare a chart incorporating that measures and present in the class. Which of the following rules is the composition of a dilation of scale factor 2, then a translation of three units to the right? a) (2x+3,y) b) (2x+6, 2y) c) (2x +3, 2y) d) (2x+6, y) Given the right triangle, evaluate: sin 0.