Question:
If $x~ = ~2~cos~\theta~-~cos~2~\theta ~~and ~~y~ = ~2~sin~\theta~ - ~sin~2~\theta$, prove that $$~\frac{dy}{dx} = tan~(\frac{3\theta}{2})$$.

How do I convert, $$\frac{dy}{dx} = \frac{cos~\theta~-~cos~2\theta}{sin~2\theta - ~sin~\theta}~~to~~tan~(\frac{3\theta}{2})$$ ?

Question

Question:
If $x~ = ~2~cos~\theta~-~cos~2~\theta ~~and ~~y~ = ~2~sin~\theta~ - ~sin~2~\theta$, prove that $$~\frac{dy}{dx} = tan~(\frac{3\theta}{2})$$.

How do I convert, $$\frac{dy}{dx} = \frac{cos~\theta~-~cos~2\theta}{sin~2\theta - ~sin~\theta}~~to~~tan~(\frac{3\theta}{2})$$ ?

akashdeepdeb · Answer

@jim_thompson5910 
@ganeshie8  ?

random231 · Answer

cosa-cosb= -2sin(a+b)/2sin(a-b)/2

sina-sinb=2cos(a+b)/2cos(a-b)/2

akashdeepdeb · Answer

Baah!
I always forget using that.
Thanks. :)

random231 · Answer

lol np :D