Trig identities Definition and 126 Threads

Theres a few... Write each expression as a single trigonometric ratio or as the number 1. 1) sint+(cott)(cost) 2) (sec x)(sin^2x)(csc x) For number one I went like this: sin t + ((1/cot)(cos/1)) sin t + (cos t/cot t) sin t + (cos t/1)( sin t/cos x) (sin t cos t)/1 + (sin t cot...

I just don't get this stuff. I've been trying on my own with the book. Also, is there a better way to post this? Homework Statement tanx 1 + secx _________ + _________ = 2csc x 1 + secx tanx I need to prove that this side equals the other. Homework...

I'm solving a pretty descent trig identity question, but I'm stuck. I'm not going to type out the original question, but here the section that I'm stuck on: sin^4x + cos^4x and here is what I have to prove: 1-2sin^2xcos^2x I know that I'm really close, I just can't get this section. Any help...

[SOLVED] Proving Trig Identities Homework Statement Prove that tanx - sinx---=---- tanxsinx ________------- _________ tanxsinx -------- tanx + sinx Homework Equations Is this impossible, so far it has been for me, what about you? The Attempt at a Solution I...

Homework Statement 4.59 x 10^-4 = Sin^3(x)/Cos(x) Solve for XHomework Equations Sin(x)/Cos(x) = Tan(x) The Attempt at a Solution We can make Sin^3(x)/Cos(x) into Tan(x)Sin^2(x), but I don't think that helps... What trick do I use?

[SOLVED] Trig Identities and Double Angle Formulas Homework Statement If tan(a) = 1/5 and tan(b) = 1/239, find tan(4a - b) Homework Equations tan2x = 2tanx/1-tan^2x tan(x-y) = tanx - tany/ 1 +tanx tany The Attempt at a Solution tan (4a - b) = (tan4a - tanb)/(1 + tan4a tanb)...

cos(90+theta) = sin(theta) sin(90+theta) = -cos(theta) cos is negative in 2nd quad sin is positive in 2nd quad i'm looking at some soln's and i just need clarification, thanks!

can anyone help me understand the following and how to apply them: tig identities sum and diff. indentities multiple angle indentities I'd really appreciate it. Thanx

Does anyone know where I can get a nice large trig identities poster that I can put up in my dorm so I don't always have to look through wikipedia?

\cos (t)=\cos(t+2\pi) I know it is kind of silly, but I need to do it. I could have sworn that a sum formula would have worked, ie., \cos(\alpha+\beta)=\cos \alpha \cos \beta -\sin \alpha \sin \beta but when I sub in t and 2\pi for the RHS, I am getting -\cos t Where did I go wrong...

Could someone tell me which trig identity this chap (in a Physics textbook) is using to turn sin(Kx)sin(2Kx) into sin^2(3Kx/2) - sin^2(Kx/2) Cheers.

Ok this is my first post...so bear with me :smile: My problem is: Sin2x-1=0 I thought I recognized that Sin2x is from the double angle identities chapter so I substituted [2CosSin] for Sin2x. So I ended up with 2CosSin=1 ( I moved the one over) ...and then I got stuck... am I...

hey guyz...ok iv been trying to figure this question out for so long...and i jus can't.i get up to a certain point and then i jus get confused.so if anyone can help me that would be great! Prov that: Cos^2x + Cotx ÷ Cos^2x – Cotx = Cos^2x (tanx) + 1 ÷ Cos^2x (tanx) -1

the follwing trig identity is used alot...but i am unable to proove it because i don't know wat to start with in solving it... sin2x=2tanx/(tan^2x+1) it invlves the double angle formulae i know that obviously, i tried substituting sin and cos into the RHS of equation and get my answer...

Hi, in this question i am nt sure the best way to tackle it! it follows proove the following 2sinxcosx=sqrt(3)-ssqrt(3)sin^2x for 0<=x<=360 i tried using the doble angle formulae on the right, putting all on one side therefore =0 (anticipating a quadratic equation) having...

Trig Identities Help...Arrrggghhh! :) I typed all of this out but the system then said I was not logged in and I lost it all...don't have time to retype everything. note: the ^ symbol is like "squared" for example, if I have 4^2 , that would be "four squared" or 4 times 4 = 16...

1. Cos x (sec x + cos x csc^2 x) = csc^2 x I got as far as this... 1 + cos^2 + cos/sin^2 = csc^2 2. tan x(sin x + cot x cos x) = sec x

i had a test and i got a 55 can someone show me how to do these with the steps if possibleverify each of the folloring trigonomic identities 1) 2sin^2x - 1/sinx-cosx = sinx+cosx* did my steps wrong 2) cot^2x-cos^2x = cos^2xcot^2x didnt get an answer <no clue how to do simplify 1)...

I can't get anywhere with these three identities. Any tips? \frac{(\sec \theta - \tan \theta)^2 + 1}{\csc \theta(\sec \theta - \tan \theta)} = 2 \tan \theta \frac{\sin^3 \theta + \cos^3 \theta}{\sin \theta + \cos \theta} = 1 - \sin \theta\cos \theta (2a\sin \theta\cos \theta)^2 +...

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:

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!

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

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.

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...

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