identities Definition and 422 Threads

Solve for x 3sin(x+10)=4cos(x-10) I tried changinf everything into tan nothing out. I tried expaning the brackets and collecting like terms, that didnt work out either. Please help.

I have been trying to solve this question for some time but I just cannot find the right solution: Simplify: 4cosec^2X + (4cosec^2X)(cot^2X)

As I rack my brains to solve(or atleast pretending) to prove Trig identites. What is it application in real life? :cry:

How can I use trig identities to let me differentiate \sin \left ( x + \frac{\pi}{2} \right) and 3 \sin x - 2 \cos x?

ok...this was meant to be a fun problem but looks like I don't deserve to have fun! How am I meant to derive trig identities like sin(x)cos^3(x) from some complex **** like \left( {e}^{{\it ix}} \right) ^{n}={e}^{{\it ixn}}! I just don't get the idea! :cry:

I need help on the following problem. (attached) Thanks

determine following setd of vectors in F(-infinitity, infinitiy) are linearly independent (using appropriate identities) 0, [cos (pi*x)]^3 , [sin 3*pi*x]^5 pls help !

cos x - cos y sin x - sin y sin x + sin y + cos x + cos y = 0 or to see better i guess... (cos x - cos y)/(sin x + sin y) + (sin x - siny)/(cos x + cos y) = 0 can you guys help me? I'm really stuck on this!

I'm having problems with it at school lately, I am not going to layout every single problem and ask for help. I am just wondering if there is a better approach to it rather than trying to solve one side in order to get it to equal the other side. For example, sin^2 x + cos^2 x = -cos^2 x - sin^2...

Trig identities please help In triangle ABC if sin (A/2) sin (B/2) sin (C/2) = 1/8 prove that the triangle is equilateral please show steps

I can, for the mort part, understand how to derive and "proof" most of my Identity work, but some of the more complex (in my feeble opinion) problems give me quite a bit of trouble. Can anyone explain these? "Use the fundamental identities to simplify to sines and cosines: tan(^2)x -...

Hi, the question is 2sin^2 + sinX -1 = 0 I think the next step is then 2(1-cos^2)+cos^2=0 Did I do something wrong because I cannot seem to continue the question?

How do you find the identity for sin(a+b) using algebra or calculus? I already know how to do it with geometry and by using imaginary numbers.

A little confused on how to begin the problem _1__ - tanx sinx = cosx cosx I know you change tanx to sinx/cosx but I can't seem to finish the problem, not sure if it is arithmatic errors or what?

How can you prove: cos(A+B)=cosAcosB-sinAsinB and similarly sin(A+B)=sinAcosB+cosAsinB If the proofs arent very complicated, I would appreciate you giving me hints first so maybe i can work them out on my own. Btw i am looking for an algebraic proof, not one with graphs & triangles.

I don't get where these two identities come from: (logn)^{logn} = n^{log(logn)} and (logn)^{log(logn)} = e^{(log(logn))^2}

I can't get these 3 questions, can someone help me? 1. cotB [ (tanA + TanB) / (cotA+cotB) ] = tan A 2. (sin^2A + 2cosA - 1) / (2 + cosA - cos^2A) = 1 / (1+ secA) 3. cos^3A + sin^3A = (cosA+SinA)(1-SinAcosA) please help out on these, thanks in advance. U can write the / sign as...

Do self-awareness, social relativity, predestination, adaptation, deity or other circumstances determine who we really seem?

Hi all, I have a question proving an identity: sin(4x) = 4sin(x)cos^3(x)-4sin^3(x)cos(x) I can't seem to figure it out. I know I should be using the known identities: sin(2x) = 2sin(x)cos(x) and probably: cos(2x) = 1-2sin^2(x) but I'm stuck. Please help! Thanks!

Trig Identities question for test tomorrow Help! Need some help with these two problems: Thanks in advance if you could answer them: sin (X) / Cos (x) - 1 = show work Sec ^2/ cot (x) - Tan ^3x = Tan X show work to prove last one Sec x - Cos x/tanx = sinx show work to prove

Hi, today I was writing my Identities final test and got stuck on one question which I couldn't solve. The question was: If sinB=-\frac{5}{13} find the exact value of tan2B. I've got this far, correct me if I went wrong anywhere: tan2B=\frac{sin2B}{cos2B}=\frac{2sinBcosB}{2cos^2B-1}...

My friend sent me some Trigonometric proving identity questions to practise and i am usually good at them but i haven't done them for a while so i have gotten a bit rusty plus these ones to me are very difficult so i would like some assistance. Prove 1/1+sin + 1/1-sinx = 2secsquaredx. ok so...