# Hi i posted this before but I wanted to ask Bobpursley a few questions on his reply 1)For the first function you used cosine when they ask for sin, why is that?

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### Precalc(attn Bobpursley)

Hi i posted this before but I wanted to ask Bobpursley a few questions on his reply 1)For the first function you used cosine when they ask for sin, why is that? Also why did you put .5 in the beginning and end of the function? 2)For the second question why did you put 10 in ...

### Jiskha

I typed several questions and answers regarding the subject of Geography, and suddenly, as I was waiting for a reply from Ms. Sue, it seemed as though my questions were deleted from the webpage where all of the other questions are posted. I do not know where I may be able to ...

### Pre-Calc

I am really struggling with how to do these problems, I posted them a few minutes ago but the answers/work shown was incorrect. 1) a) Use an Addition or Subtraction Formula to write the expression as a trigonometric function of one number. cos 12° cos 18° − sin 12° ...

### inverse

If f(x)=cosx + 3 how do I find f inverse(1)? Thanks y = cos(x) + 3 the inverse of this is x = cos(y) + 3 solve for y and you have your inverse The cos function only has a range of [-1,1], so the range of f(x) is [2,4]. this means f inverse of 1 doesn't exist. I didn't ...

### Math HELP!

I posted a few questions and then went back and posted how I thought they were supposed to be answered. Could someone please locate my earlier questions and tell me if I am on the right track?

### Math - derivative of sinusoidal (check)

a) Find a function y=f(x) that satisfies the differential equation dy/dx = fifth derivative. This is one of the questions in my practice test, I tried the basic equation of the trig function such as f(x)= sin(x) or f(x)=-sin(x) however in the fourth derivative they reach the ...

### Pre-Cal: Word Problem

I'm having a lot of trouble on this word problem. Can someone help me plz? To define the inverse sine function, we restrict the domain of sine to the interval ______. On this interval the sine function is one-to-one, and its inverse function sin^−1 is defined by sin^&#...

### trig-reply to Reiny

RE: (- sin (x/2) /( 2 sin (x/2) + cos (x/2)) is an alternate representation for, 1 / ( 4 tan (x/2) + 2 ) Thanks for your help, sorry I posted 3 times, I thought you didn't understand what I needed. I really do appreciate your time spent. just for your FYI, if you are ...

### Math CONTINUATION OF QUESTION FROM bobpursley

Thank you for answering the question before bobpursley, I understand how you did the deriv of inside, outside, but how do I now do the second derivative since you have the extra -18x^2 in the numerator?? Thank you very much! (I suppose I have to brush up on my derivatives) ...

### another precal

i have two questions for you to check please! 6cos^2x+5cosx-4=0 where 0degrees < or equal to 0 which is < or equal to 360. I got that this factors to (3x+4)(2x-1) so the answer is x= -4/3 and x= 1/2 ?? right? and the second question: determine sin2theta, cos2theta, and ...

### ATTN bobpursley

On Thursday October the Second, you gave a reply to "martha" regarding the movie chariots of fire. I have posted a response there of my own because I feel that your feedback was misguided. Could you please read my message and then get back to me?

### Physics recheck

Let f be the frequency, v wav the speed, and T the period of a sinusoidal traveling wave. The correct relationship is: a)f=1/T b)f=vwav + T c)f=vwavT d)f=vwav/T e)f=T/vwav My thoughts: Since frequency is equal to T=1/f so f=1/T. Vwav is connected to f by the equation v=lambda...

### Trig

Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < 2pi Find: sin (v + u) cos (v - u) tan (v + u) First compute or list the cosine and sine of both u and v. Then use the combination rules sin (v + u) = sin u cos v + cos v sin u. cos (v - u) = cos u cos v + ...

### math

Eliminate the parameter (What does that mean?) and write a rectangular equation for (could it be [t^2 + 3][2t]?) x= t^2 + 3 y = 2t Without a calculator (how can I do that?), determine the exact value of each expression. cos(Sin^-1 1/2) Sin^-1 (sin 7pi/6) x= t^2 + 3 y = 2t ...

### Trig

In ABC, vertex C is a right angle. Which trigonometric ratio has the same trigonometric value as Sin A? A Sin B B Cosine A C Cosine B D Tan A

### DEAR REINY

dear reiny i am sim who posted 4 questions this morning i am in dubai and my final examinations are after 13 days and by the way those questions were not my homework or assignment those were some sums which we get on our school website and i had a doubt in those questions but ...

### the novel "Ordinary People" by Judith Guest

Has anybody read this book? I have a few questions to ask, I've read the book but forgotten a few things reply ASAP!

### Calculus

How do I graph sin and cosin example: graph y=-4sin(x + 3.14) Your function is the sin function shifted by pi units to the left. You need to study the sin function and know how to graph it. There should be a picture of it in your text, it's a very commonly used funtion that ...

### English (parts of speech)

1)Few comic strip are really comical 2)Few attended the meeting (Few is: adjective, verb ,adverb, preposition) (the first and the second are different 3)Before the telecast, we were all nervous 4)Before you leave, let me have your address Before is in the two sentences:Noun,...

### english

For questions 13-15, select the answer that correctly identifies the part of speech of the all caps word. 1. Katrina wanted to vist her grandmother AND grandfather over the weekend. a. conjuntion b. noun 2. "OH" her mother said, "why don't we go Saturday. a. noun b. ...

### trig

Reduce the following to the sine or cosine of one angle: (i) sin145*cos75 - cos145*sin75 (ii) cos35*cos15 - sin35*sin15 Use the formulae: sin(a+b)= sin(a) cos(b) + cos(a)sin(b) and cos(a+b)= cos(a)cos(b) - sin(a)sin)(b) (1)The quantity = sin(145-75) = sin 70 = cos 20 note that...

### Computer Questions

I posted some computer questions and my answers on Saturday. They should be on somewhere between pages 2 through 10. would you please check my answers for me? There are about 16 questions and answers. Thank you!! It will say "computer questions" Thank you. Yup. I got it :) But...

### Calculus

The motion of a spring that is subject to dampening (such as a car's shock absorber)is often modeled by the product of an exponential function and a sine or cosine function. Suppose the equation of motion for a point on such a spring is s(t)=3∗e^(−2t)sin(3ðt) ...

### Calculus

1) The period of a trig. function y=sin kx is 2pi/k. Then period of y=sin^2(pi.x/a) should be 2pi/(pi/a)=2a, but somewhere it is given as a. Which is correct? 2) The period of r=sin^3(theta/3) is given as 3pi. How is it worked out? Is it because after theta=0, the function ...

### TRIG!

Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6 x=1 - (3/4)sin^2 2x work on one side only! Responses Trig please help! - Reiny, Monday, February 23, 2009 at 4:27pm LS looks like the sum of cubes sin^6 x + cos^6 x = (sin^2x)^3 + (cos^2x)^3 = (sin^2x+cos...

### Trigonometry

IM STUCK ON THESE :( 1. What is the equation for shifting the standard sine curve +2 units horizontally? A. y = sin (x + 2) B. y = sin x + 2 C. y = sin x − 2 D. y = sin (x − 2) 3. What is tan-¹ √3/3 ? A. π/4 B. -π/3 C. π/6 D. -π/4 4. cot...

### Trigonometry

IM STUCK ON THESE :( 1. What is the equation for shifting the standard sine curve +2 units horizontally? A. y = sin (x + 2) B. y = sin x + 2 C. y = sin x − 2 D. y = sin (x − 2) 3. What is tan-¹ √3/3 ? A. π/4 B. -π/3 C. π/6 D. -π/4 4. cot...

### Math

Rewrite the expression in terms of the first power of cosine sin^4(x)

### calculus

rewrite the expression in terms of the first power of the cosine. sin^8x

### Spherical Trigonometery

I am trying to apply the formula cos c = cos a x cos b + sin a x sin b x cos C to find the length of c in my spherical triangle. I am working with 2 examples in a book in which the answers are given. In the first example all the sines & cosines calculated are positive and I ...

### Trigonometry

Use the power-reducing formulas to rewrite the expression in terms of the first power of the cosine. [#1.] (sin^4x)(cos^4x) [#2.] (sin^4x)(cos^2x)

### Calculus

After t hours of an 8-hour trip the distance a car travels is modeled by: D(t)= 10t + (5)/(1+t) - 5 where D(t) is measured in meters. a) derive a formula for the velocity of the car. b) how fast is the car moving at 6 hours? c) derive a formula for the car's acceleration. I'm ...

### Math

rewrite the expression in terms of the first power of cosine. cos^3(x)sin^4(x)

### Trigonometry

rewrite the expression in terms of the first power of cosine. cos^3(x)sin^4(x)

### Math

Rewrite the expression in terms of the first power of the cosine sin^8(x) how do i do this plz help !!

### Calculus

Consider the function f(x)=sin(1/x) Find a sequence of x-values that approach 0 such that sin (1/x)=0 sin (1/x)=1 sin (1/x)=-1 Is sin sin (1/x)=0 and sin (1/x)=-1 does not exist. What is sin (1/x)=1 then.

### Physics - Frequency

This is in reply to a previous post, I'm not really sure whether replies to posts that are several days old are viewed by anyone, so I'm reposting just in case. In reply to bobpursley's post, I just want to ask, how would you know how long it takes for the sound to reach you? ...

### To: Bobpursley

Thanks for your reply! I have some questions about my AMERICA ONLINE service that's why I asked "How can I e-mail to America Online? Is there any website where I can write my comments or questions to America Online? (Like Feedback) I found a website on GOOGLE but there was a ...

### Graphing trigonometric function

sine and cosine have a period 2pi tangent and cotangent have period pi Can someone explain why? thanks a lot. well tangent is sine/cosine and there a place where the tangent function is undefined and that is where the asymptotes occur. the same is true with the cotangent since...

### sine and cosine

Simplify and write the trigonometric expression in terms of sine and cosine: sin x + (cot x)(cos x) = (1/f(x)) f(x)= ?

### Math 2nd question

Express as a single sine or cosine function (note: this is using double angle formulas) g) 8sin^2x-4 I just don't get this one. I know it's got something to do with the 1-2sin^2x double angle formula. It's the opposite though? :S h) 1-2sin^2 (π/4-x/2) = 1-sin^2(π/4-x...

### @Kemon

I deleted your 19 questions because you showed none of your work and posted no answers. If you'd like us to check a few of your answers, please repost no more than five questions along with your answers.

### Reply to grant about a regression problem

This is a reply to the question posted here http://www.jiskha.com/display.cgi?id=1178989522 As I explained there, you can find the parameters by defining: x1 = Sin(0.49 t) x2 = Cos(0.49 t) and treat this as an ordinary linear regression problem. If we denote the height by Y, ...

### Algebra II

Part 1: Using complete sentences, compare the key features and graphs of sine and cosine. What are their similarities and differences? Answer: The sine graph will always pass through (0, 0), While the cosine graph wouldn't. If the graph is 2cosx, it will pass through (0, 2). ...

### Algebra

89. Solve for x in the equation: 6/7x - 6 = -2 I posted this before, and this is the reply I got from someone: multiply both sides by 7 6x-42=-14 add 42 to each side 6x=28 x=14/3 But I don't get how this is done because to eliminate 6/7 shouldn't I multiply by 7/6, and not ...

### Math PLEASE HELP

No one was answering my questions for the first question I posted so I posted it again. answers for 12345: 1. 9 3/5 2. 4 1/2 3. 4 3/4 4. still 7 6/9 5. still 10 16/18

### Calculus

Consider the function f(x)=sin(1/x) Find a sequence of x-values that approach 0 such that (1) sin (1/x)=0 {Hint: Use the fact that sin(pi) = sin(2pi)=sin(3pi)=...=sin(npi)=0} (2) sin (1/x)=1 {Hint: Use the fact that sin(npi)/2)=1 if n= 1,5,9...} (3) sin (1/x)=-1 (4) Explain ...

### Calculus

Consider the function f(x)=sin(1/x) Find a sequence of x-values that approach 0 such that (1) sin (1/x)=0 {Hint: Use the fact that sin(pi) = sin(2pi)=sin(3pi)=...=sin(npi)=0} (2) sin (1/x)=1 {Hint: Use the fact that sin(npi)/2)=1 if n= 1,5,9...} (3) sin (1/x)=-1 (4) Explain ...

### Math (trigonometric identities)

I was given 21 questions for homework and I can't get the last few no matter how hard and how many times I try. 17. Sinx-1/sinx+1 = -cos^2x/(sinx+1)^2 18. Sin^4x + 2sin^2xcos^2x + cos^4x = 1 19. 4/cos^2x - 5 = 4tan^2x - 1 20. Cosx - sinx - cos^3x/Cosx = sin^2 - tanx 21. Sin^2x...

### Trig

Solve in terms of sine and cosine: sec(x) csc(x)- sec(x) sin(x) so far I have: 1/cos(x) 1/sin(x) - 1/cos(x) sin(x) I am not sure where to go to from there. The book says the answer is cot(x) or cos(x)/sin(x) Thank you in advance.

### CALC

Let f(x) be the function e^sin(x/10). If you wanted to estimate the area under the curve for this function from 3 to 5, how many intervals would you need to use to be sure that your upper and lower bounds differered by no more than .01?

### math

Use the formulas for lowering powers to rewrite the expression in terms of the first power of cosine. sin^6(x) Answer=__________ ~Thank you.

### drwl / bobpursley please check

I had posted three questions at 1:48pm, 2:40pm and 2:41pm and I am having problems with them. Can you please check them for me. Thanks! Repost if you are not satisified with the responses.

### Math repost

I posted this question before at 7:14 I think the answer to it is 0. cot(40) - ((sin(50))/(sin(40)) = ? these are also degrees steps too please. I thought since 50+40= 90 then that part would be 1, but then how would cot 40 turn out to be 1

### gnozahs

I removed about ten questions you posted this morning. There was no indication of what you had done, what your thinking was, or what you wanted from us. We are not going to do homework for you. If you want hints on these calculus questions, say so, or ask what you want. Just ...

### pre calc

The Identity Function The Squaring Function The Cubing Function The Reciprocal Function The Square Root Function The Exponential Functional Lo The Natural Logarithum Function The Sine Function The Cosine Function The Absolute Value Function The Greatest Integer Function The ...

### math

actually, in a addition to the question i posted a few minutes ago, can someone please help me with a few actual specific questions? thanks so much i'm very confused and i've been working on these all day. *Literal Equations* ~solve for x ax + bx = 8ab ~solve for y my - ny = m...

### Calculus - Second Order Differential Equations

Posted by COFFEE on Monday, July 9, 2007 at 9:10pm. download mp3 free instrumental remix Solve the initial-value problem. y'' + 4y' + 6y = 0 , y(0) = 2 , y'(0) = 4 r^2+4r+6=0, r=(16 +/- Sqrt(4^2-4(1)(6)))/2(1) r=(16 +/- Sqrt(-8)) r=8 +/- Sqrt(2)*i, alpha=8, Beta=Sqrt(2) y(0)=2...

### Physics (CHECK)

One student is pushing on a chair with a force of 260.6 N directed at an angle of 30 degrees above horizontal while a second student pushes on the same side of the chair with a force of 21.0 N at an angle of 15 degrees below horizontal. What is the magnitude, in N, of the sum ...

### @Incognito

I'm putting you in time-out for a few days so you can think about a few things. 1. Do not post in all-caps. It's considered shouting (and rude) online. 2. If you don't like how this website is run, go find another. 3. If you have homework questions, then ask them and have ...

### English

Which sentence is correct: I wanted to tell you something before I head to town. or I wanted to tell you something before I headed to town. I think it is the first one, but I'm not sure.

### To Fay1985 - math

Your post was removed. Please tell us your thinking on the 25 questions you posted. Attempt some answers, and we'll be glad to help you. Also -- I don't believe that you posted complete information for many of the questions.

### Quantum mechanics, eigenfunctions!

Determine if the function sin(x)*e^(ax) where a=constant is an eigenfunction of the operators d/dx and d^2/(dx)^2 Okay. My understanding is that you use the operator and perform its "thing" on the function. In this case, you will have to find the 1st derivative of sin(x)*e^(ax...

### french - final draft

Well.. i posted this before and I re-edited a few things. I need suggestions and editing please :)

### Thank you (bobpursley)! (no reply needed)

No reply needed.

### Calculus

Hello. I have a few questions from my study guide, that I need to know to study for my test. 1) x^(2/3)*((5/2)-(x) a) determine the ordered pairs of the local extrema of the function. Use the second derivative test. B) determine the ordered pairs of all inflection points of ...

### Business Communications

Write a business letter to the company or organization that's offering something you want and ask four questions that are important to you. Be sure to include enough background information, so the reader can answer your questions satisfactorily. Hollywood Vacation Giveaway 123...

### Calculus

Hello, I just wanted to verify if my work was good. Calculate the following integral by parts: ∫ upper limit is 1/5 and lower limit is 1/10. of 10sin^-1 (5x)dx so first I named the variables: u = 10 sin^-1 (5x) du = 50 / sqr(1-25x^2) dv = dx v = x so we get: = 10 sin^-1...

### ok (my posts mysteriously vanishes...)

I posted a reply thanking both bobpursley and dr.bob (mild criticism)... I don't see the post. What happened? Was it removed? I saw your post thanking Bob Pursley and me. Many thanks for the thanks. All of us like to think that we lend a helping hand. Both individually and as ...

### Math Algebra

hi guys need help with a few questions. 1. Which equation represents the axis of symmetry of the function y = 2x^2+4x-6? A. y= 1 B. x= 1 C. x=3 D x= -3 2. & 3. What are the coordinates of the vertex of the graph of the function - 2. y = -x^2+6x-11 A. (3,-2) B. (3,16) C. (-3,-...

### physics Again

bobpursley can you please check my reply to your post about my question? I am not sure if I did my equation correctly. Thanks

### pre-calculus

Rewrite the following expression as an algebraic function of x sin(arccos(x/2)) I know sine is y, which is opposite over hypotenuse. I also know that arccos is the inverse of cosine. I'm confused on what the question is asking and what to do with the x. Please help! Thanks

### algebra 2

Posted by hellogoodbie on Saturday, January 16, 2010 at 3:24pm. Posted by hellogoodbie on Saturday, January 16, 2010 at 2:59pm. How is this problem done? IF f(x)=2x^2-8x-3 FIND f(-2) algebra 2 - bobpursley, Saturday, January 16, 2010 at 1:42pm Put in for x the value -2, and ...

### calculus

Could someone check my reasoning? thanx Find the derivative of the function. sin(sin[sinx]) I need to use the chain rule to solve. So I take the derivative sin(sin[sinx) first. Then multiply that by the inside which is the derivative of sin[sinx]. And multiply that by ...

### Calculus

Hello, Could somebody kindly check my answer for the following question? Find the derivative of the following function: h(x)=3e^(sin(x+2)) h'(x)=3'(e^(sin(x+2))+3(e^(sin(x+2))' h'(x)=0(e^(sin(x+2))+3(e^(sin(x+2))(cos(1)) h'(x)=3cos1(e^(sin(x+2)) I would greatly appreciate your...

### MATH

1.)Find the exact solution algebriacally, if possible: (PLEASE SHOW ALL STEPS) sin 2x - sin x = 0 2.) GIVEN: sin u = 3/5, 0 < u < ï/2 Find the exact values of: sin 2u, cos 2u and tan 2u using the double-angle formulas. 3.)Use the half-angle formulas to determine the ...

### Math

1) Prove that for every x>=0 and 0<a<1 x^a-ax<=1-a 2)prove that for 0<=x<=1: x^m*(1-x)^n<= (m^m*n^n)/((m+n)^(m+n)) can someone please guide/help me in about how to solve and or approch these questions? (I know I have already posted it before but i think it...

### math

i have a few questions cosx + cosx =2secx ----- ----- 1+sinx 1-sinx cos(x-B)-cos(x-B) = 2sinxsinB csc2x= 1 secx cscx --- 2 cotx= cos5x+cos3x ----------- sin 5x-sin 3x

### physics

anyone who knows the answer to this question please show your work. drwls i know i posted this queestion before but you didn't reply to my comment. Your friend has climbed a tree to a height of 6.00 m. You throw a ball vertically up to her and it is traveling at 5.00 m/s when ...

### Science-bobpursley

Thanks for helping me with al those parts bobpursley. If you have time, can you also check my questions please. Thank you very, very much in return. My post is on the second page.

### math 140

I have two questions posted that has not been answered please help. The questions were posted on March 18 please help.

### Trig

Simplify sin x cos^2x-sinx Here's my book's explanation which I don't totally follow sin x cos^2x-sinx=sinx(cos^2x-1) =-sinx(1-cos^2x) =-sinx(sin^2x) (Where does sine come from and what happend to cosine?) =-sin^3x

### Calculus

Consider the function f(x)=sin(1/x) Find a sequence of x-values that approach 0 such that sin (1/x)=0 sin (1/x)=1 sin (1/x)=-1 Is sin sin (1/x)=0 and sin (1/x)=-1 does not exist. What is sin (1/x)=1 then. How would I show the sequence of values, any help would be greatly ...

### AED

I know I posted this but AI wanted to pose what i have so far and need more info. I have this so far: The hands-on learning in a science classroom when few resources are provided by the school can be the discovery bottles that the teacher can make, sensory table and you can do...

### Physics

A vertical spring with a spring constant of 450 N/m is mounted on the floor. From directly above the spring, which is unstrained, a 0.30 kg block is dropped from rest. It collides with and sticks to the spring, which is compressed by 3.0 cm in bringing the block to a momentary...

### Calc

Find the exact total of the areas bounded by the following functions: f(x) = sinx g(x) = cosx x = 0 x = 2pi I set my calculator to graph on the x-axis as a 2pi scale. The two functions appear to cross three times between x = 0 and 2pi. (including 2pi) Now, from top to bottom, ...

### Math

Hi, this is a question I posted a couple of days ago and answers below.I am still really confused and unfortunately can't copy a picture into this. I thought it would be y-x but have no idea how to calculate that, but as the pistons move in towards each other, wouldn't the ...

### Physics

Why is sin theta used in the torque formula while the work formula uses cosine theta?

### question+ stuck

how is the graph of f(x)= x^2-4x be used to obatin the graph of y=g(x)? I am stuck and unsure how to get out of this one so can you please help? thanks! You must define g(x). Is g(x) the inverse function of f(x)? well the function f(x)= x^2-4x has two zeros x= o and x-4 Yes. ...

### Health

Hi again..sorry I havn't been asking questions these days as my sister (y912f) is always on :P I wanted to know whether it is better to brush your teeth after eating or before. Because mostly everyone does it before but I don't see the point when they're going to get dirty ...

### maths

Choose the two options which are true for all values of x 1) cos (x) = cos ( x – pie/2) 2) sin (x + pie/2) = cos (x – pie/2) 3) cos (x) = sin (x – pie/2) 4) sin (x) = sin (x + 4pie) 5) sin (x) = cos (x – pie/2) 6) sin^2 (x) + cos^2 (x) = pie would it be 1 and 3 ?? I ...

### Math (Trig)

sorry, another I can't figure out Show that (1-cot^2x)/(tan^2x-1)=cot^2x I started by factoring both as difference of squares. Would I be better served by writing in terms of sine and cosine? Such as: [1-(cos^2x/sin^2x)]/[(sin^2x/cos^2x)-1]=(cos^2x/sin^2x)

### Pre Cal

how would i find the degrees of cos x= 3/2 if (0 <or= theta < 360)? i've tried putting it in my calculator with cosine^-1 but im just getting err:domain. Please help! The cosine function only goes from -1 to +1. There is no solution to cos x = 3/2. thank you!

### Ms. Sue

Posted by Anonymous on Monday, February 17, 2014 at 9:02pm. Ms. Sue you banned me for giving answers to none existent questions, here only 2 questions were asked, quite a few people gave 3 answers. Why was I banned for this if other people do it.

### Trigonometry

Can you show steps on deriving the identity from the sum and difference formulas for cosine: sin a sin b = (1 / 2)[cos(a – b) – cos(a + b)]

### Pre-Calculus

Write the following expression as the sine, cosine or tangent of an angle. cos 3x cos 2y + sin 3x sin 2y

### Evaluation-repost

Reposting because it has gone down to the second page! Evaluate 1. sin(tan inverse sqrt(x^2-2x)) 2. tan (sec inverse 3y) For 1. draw a right triangle and label the opposite leg sqrt(x^2-2x), the adjacent side 1 and the hypotenuse x-1. Do the calculations to see why this is so...

### Definite integral by parts (correction)

Hello, I just wanted to verify if my work was good. Calculate the following integral by parts: ∫ upper limit is 1/5 and lower limit is 1/10. of 10sin^-1 (5x)dx so first I named the variables: u = 10 sin^-1 (5x) du = 50 / sqr(1-25x^2) dv = dx v = x so we get: = 10 sin^-1...

### Math

use the sum and difference identities to find the cosine angle cos pi/9 cos pi/3 - sin pi/9 sin pi/3 I do not know how to solve this because pi/9 is not on the unit circle.