Trigonometric identity (1 Viewer)

[coyazayo]

Hi everyone

Q1. Write down an equivalent expression consisting of one term for each of the following

A. (1-tan^2(θ/2))/(1+tan^2(θ/2))

B. (1-cos4θ)/(1+cos4θ)


Q2. Prove that (without using half-angle formula) cos22.5= \frac{\sqrt{2+\sqrt{2}}}{2}

So irritating to write some of these questions down

 

[leehuan]

 

[Paradoxica]

A: reverse tangent half angle

B: double angle expansion

and for the last one, begin by simplifying (1-cos(2θ))/sin(2θ)

then input an appropriate value of θ