The Student Room Group

Parametric differentiation, using identities

So ive got this, how do I work it through to get cot(theta/2)? ( i know theyre both equivalent)

Thanjs
IMG_20160302_105029.jpg
Reply 1
Please post the question. Assuming you are correct (and nobody has any idea since you have not posted the question,). You might start by dividing top and bottom by cosθ\cos \theta
Reply 2
Original post by JohnnyDavidson
So ive got this, how do I work it through to get cot(theta/2)? ( i know theyre both equivalent)

Thanjs
IMG_20160302_105029.jpg


Try writing sin(θ)\sin(\theta) and cos(θ)\cos(\theta) in terms of sin(θ2)\sin(\frac{\theta}{2}) and cos(θ2)\cos(\frac{\theta}{2}) using the double angle formulae.
Reply 3
Original post by joostan
Try writing sin(θ)\sin(\theta) and cos(θ)\cos(\theta) in terms of sin(θ2)\sin(\frac{\theta}{2}) and cos(θ2)\cos(\frac{\theta}{2}) using the double angle formulae.

Which is a whole lot better idea.
Original post by nerak99
Please post the question. Assuming you are correct (and nobody has any idea since you have not posted the question,). You might start by dividing top and bottom by cosθ\cos \theta


Tried to uploaf it just now, but got an error. My answer ive worked to, is equivalent to the correct answer though (so just need to work it trhough from where ive got to)

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