Cos Definition and 317 Threads

Homework Statement I have a graph of 5 = cos 0 and 1 = cos 180. The question is find the values for integers p and q y = p + q cos x p and q are integers How do I go about doing this Thx

How to prove Sigma^infty_{n=1} r^n*cosn(t) = (r cos (t) - r^2)/(1-2r*cos(t) + r^2) ?? Homework Statement This question has two parts and I need help with the first part (I think) because then I should be able to make a start on the second part. The exact question is (where t = theta)...

Homework Statement how would one calculate 4 \int_0^{\frac{\pi}{2}} \frac{\cos^2 \theta}{(1 + \cos^2 \theta)^2} d \theta ? The Attempt at a Solution someone suggested a u = \tan \theta substitution, but i don't understand why and how this would help me. couldn't i just use u = \cos t?

Please, how can I solve this? ∫ cos x ln x dx I get this: ln x sin x - ∫sin x/x dx but how do I continue from here? Thanks in advance...

does cos + sin = 0?

In the function y=4sin(3X+Pie/4)-2 what determines the period and phase shift? I know that 4=Amplitude The answer in the back of the textbook says Period=2pie/3 Phase Shift=-pie/12

I have been asked to differentiate cos x and six...the maclaurin series versions... I have done the general and specific terms as shown below. Im not sure if these are correct? thanks General Terms cos x = ∑ (-1)n (x^(2n) / (2n)!) COS x = ∑ (-1)n (x^(2n+1)/ (2n +1) / (2n)!)...

http://www.nytimes.com/2007/01/15/washington/15trial.html?hp&ex=1168837200&en=3f7306b6311f26d6&ei=5094&partner=homepageAnd for an honest and sobering statement on the integrity of those in the white house:

another power series question... I tried it for awhile but it just got out of hand and the amount of numbers got unbearable. Q. The increase in resistance of strip conductors due to eddy currents at power frequencies is given by : X = yt divided by 2 (sinh yt + sin yt divided by cosh yt -...

Hi I've got 2 questions I am not to sure about. 1.Evaluate sinh(1.6), correct to 5 decimal places, using power series methods. I think i got the answer to this as being 3.16200 by using the series expansion for sinh "x" and putting 1.6 into the equation. 2.Determine the power series for...

hi, my question is from Modern Engineering Mathematics by Glyn James pg 177 # 17a Using the exponential forms of cos(theta) and sin(theta) given in (3.11a, b), prove the following trigonometric identities: a) sin(x + y) = sin(x)cos(y) + cos(x)sin(y) and 3.11a is: cos(x) = 0.5*[ e^(jx)...

I need to find \int \cos^2(x)\sin^7(x)dx I'm not sure what substitution to make

thanks......

I am trying to prove this equation: Sin 6x Cos 4x + Cos 4x sin 2x = Cos 2x tan 8x Tan 8x does anyone have any idea??

okay, so this particular equation involves me writing conjugate of either sin or cos, but hows that possible considering they both are real in the given problem? maybe i should convert sin and cos into their exponential form first? but then wt would be the conjugate of this...

I'm really having difficulty understanding how to approach problems in my physics class due to 1. never having taken physics before, and 2. having a professor that I cannot understand (english is not his native language, and he speaks very soft/fast). We're now doing tension in class, and I'm...

Hey, I’ve got a test in one week’s time and was studying through my textbook of geometry and trigonometry. I came across a “rule” which shows how to simplify expressions in the form of a \cos \theta + b \sin \theta but I do not understand how this “rule” works. The simplify rule: a \cos...

Yeah, I tried doing this question and just wanted to check if I was correct. Write down the derivative of \arccos (4x^2) and state the domain for which the derivative applies. \mbox{let}\ y = \arccos (4x^2), x\ \epsilon\ [-1, 1], y\ \epsilon\ [0, \pi] \Leftrightarrow x = \frac{\sqrt{\cos...

I have to calculate this without using the calculator. cos (arctan 5/12) So far i draw a triangle and i have the opposite side to be 5, adjacent to be 12, and hypotenuse to be 13. Please suggest me some hint, thanks.

Okay can anyone tell me why is this true for restriction of 0 < x < 360 sin(x)=0.15, x = 8.6 and 171.4 cos(x)=-.655 x = 130 and 230 tan(x)=0.75, x = 36.9 and 216.9 I don't see a pattern or rule... please co-ordinate me through the use of graphs if you can my teacher didn't explain it well.

Generally I am confused about the use of sin and cos in physics problems. http://img188.imageshack.us/img188/3162/eg2gu.gif The torque about the beam's attachment to the wall is: T * 8 * sin(53) Where T is the tension of the wire. Why is sin the choice and not cos? The...

Hello, could anyone help me calculate the value of x? 246.25 sin x - 676.58 cos x = -27768.42 Thank you.. James

Well, the question goes like this, A particle of mass m is trapped in an infinitely deep one-dimensional potential well between x = 0 and x = a and at a time t=0,, the wave fuction is given as Φ(x,t=0)=sin(((πx)/a))cos(((2πx)/a)) (i) What possible values may be found for energy of...

may i know how to solve [ n^2 cos(n(pi)) ]/ n^2 + 42?? i have divided it by n^2 and get cos(n pi) / (42/n^2) and i can't solve already.pls help what is the limit for cos (n pi) and sin (n pi)??

Can some one tell me how sin, tan and cos came about. I know the equations, but i want to know how it brought about.

i and the rest of my class are finding it impossible to find the answer to this part of the question: find the exact value of cos A from secA-cosA=1/2 thanks in advance

How would I do the derivative of f(x) = cos pi*x I know f'(x) cos x = - sin x but what about that pi?

Solve the following question. Give your answer in cert form .Thank you . sin-1 x + sin-1 (2x) = pie/3

3 cos x + 4 = 0 cos x = -4/3 How do I solve this? I can't take the arcsine... --- sin (3x - 40) = 0 Is the general solution 73.3 + 120k | k E I?

hey everyone, i have to show that in a triangle, there is : (A, B, C are the angles of that triangle) \sin \left( 1/2\,B \right) \cos \left( 1/2\,C \right) +\sin \left( 1/2 \,C \right) \cos \left( 1/2\,B \right) =\cos \left( 1/2\,A \right) for this one, here is what i got to...

For the traveling wave described by the formula y(x,t) = Asin(kx-wt) Then the wave is traveling in the +x direction. True or false? In the physics textbook I have, it describes a traveling wave by y(x,t) = Acos(kx-wt), using COS instead of SIN. Is there a difference between these 2...

How do I go about solving x^2y' - cos (2y) = 1 This is unlike anything I've seen so far. Or so I think.

I am supposed to find an approximation of this integral evaluated between the limits 0 and 1 using a taylor expansion for cos x: \int \frac{1 - cos x}{x}dx and given cos x = 1 - \frac{x^2}{2!} + \frac{x^4}{4!} - \frac{x^6}{6!}... i should get a simple series similar to this for...

Hi, I need to prove: (tan y + Cot y) sin y cos y = 1 I've gotten this far and got stuck: (tany + cos y) sin y cos y changed Cot to reciprical --------sin y (sin y tany + cosy) sin y cos y common demonator --------siny (sin y tany + cos...

solve for cos 3x=sin 2x using complementary angles and all i got alpha=2x. The thing is, if i got alpha 2x from sin inverse, the general formula would be \theta= n \pi + (-1)^n \alpha i get something like, so,...the problem is that i will have x in the general formuala...

How can I calculate cos 72° and sin 72° using complex numbers, and without the use of a calculator? I noticed that 5*72° = 360° so (cos 72° + i*sin 72°)^5 = 1. But, I don't quite know how to go from there.. :shy:

Hello, can someone please help me out with the following question? Express \sinh \left( {x + yi} \right) in terms of \sinh (x), \cosh(x), \cos(y) and \sin(y). Hence find all solutions z \in C of the equation \sinh(z) = i. I have little idea as to how to do this question. Here is my...

Hi I'm new here, great forum! On another thread that I can't find I found a message from jamesrc about differentiating cos of sinx that says: df(g(x))/dx = df(g)/dg * dg(x)/dx by the chain rule, this part I get and I thank james for the help the thing that confuses me is why df(g)/dg =...

cos and sin cont... Hi thanks for the help guys, I know this is more physics related but psychacoustically is it important wether cos or sin harmonic compoments are used in sound synthesis.

Can anyone tell me the difference btween cos and sin, and tell me when creating waveform why the sin function creates a sawtooth appearance and the cos function does. Any help would be appreiciated. :!) :!)

Hi This is a fairly straightforward problem but I want to do it using calculus. Here goes: Prove that \sin 1 > \cos(\sin 1). This is what I've done (I've hardly done much): Let f(x) = \sin(\cos(\sin x) - \cos(\sin(\cos(x))). I also have to show that f(x) = 0 has exactly one solution...

I'm a 7th grade student, but I study more advanced topics. I'm learning about mechanics, but it asks for sin and cos(cosin). I don't know too much about sin and cos, so I was wondering if anyone could explain it. :redface:

Hi, I've been having troubles solving this integral: \int \frac{\sin x.\cos x}{\sin^4 x + x.\cos^4 x} dx Here's how I tried it: t = \cos x dt = - \sin x dx dx = \frac{dt}{-\sin x} x = \arccos t dx = -\frac{1}{\sqrt{1-t^2}} dt -\frac{1}{\sin...

I need to show that the function {f(x)= x + cos x} has an inverse without the use of a graph. I understand that the simplest way to do this is by the using the horizontal line test, but that is not an option in this case. The professor has asked us to think intuitively about this problem, and I...

I need to show that the function {f(x)= x + cos x} has an inverse without the use of a graph. The professor has asked us to think intuitively about this problem, and I am just at a loss. Any help would be most appreciated, as I am trying not to fail this class. Thanks!

Hey folks, HERE GOES... :confused: the integral of (sin 3t)^5 cos t dt i believe you have to use u substitution but i am having trouble getting it set up correctly. Thanks for any input :smile:

Given that n = Π[2 – 2cos(kπ/ n)] ... (where Π is the product sign , from k = 1 to n-1 ) as cos2@ = 1 – 2(sin@)^2 then 2 – 2cos(kπ/ n) = 4[sin(kπ/ 2n)]^2 , for k = 1 , 2 , 3 , … n-1 then n = Π[4[sin(kπ/ 2n)]^2] = [4^(n-1)] Π[sin(kπ/ 2n)]^2 but the book then said...

Hi, How would I do the following: Find all w in C, such that cos(z + w) = cos z, for all z in C. Of course I would need to use the identity cos z = (e^iz +e^-iz)/2, but I have trouble finding w for all z. Thank you

having trouble showing that X(t) = Xo cos (wt) + (Vo/w) sin(wt) been fiddling with equations for a while and can't see it... thanks!

why cos 90 is 0?? Hello everyone got one question here... why cos 0 is 0? cos of any angle is adjescent by hypotenuse. so what is adjescent in case of 90 degree angle?? is the question clear? please reply ASAP...pls thanx in advance...