Question #895e3

1 Answer
Sep 8, 2015

For solving this problem we need to know some trigonometric ratios and identities:
1)cosecthetaθ=1/sinthetaθ
2)cotthetaθ=cos thetaθ/sinthetaθ
3)sin^2sin2theta+cos^2θ+cos2theta=1θ=1

Explanation:

For an easy solution to all proof questions its convenient to go for
L.H.S= R.H.S method:

1)in R.H.S (WE HAVE) rArr (cosec(cosecthetaθ- cotcotthetaθ)^2)2

2) using 1 & 2 rArr (1/sin(1sinthetaθ-costhetaθ/sinsinthetaθ)^2)2

3) now we get rArr (1-cos(1costhetaθ/sinsinthetaθ)^2)2

4) on splitting we get rArr (1-cos1costheta)^2θ)2 / (sinsintheta^2θ2)

5)now (1-cos1costheta)^2θ)2 can be written as :
(1-cos1costhetaθ) * (1-cos(1costhetaθ) and (and(sintheta^2θ2) can be written as :

(1-cos1costheta^2θ2) = (1-cos1costhetaθ) * (1+cos(1+costhetaθ)#

6) so,we get
(1-cos1costhetaθ) * (1-cos1costhetaθ) / (1-cos1costhetaθ) * (1+cos1+costhetaθ)

7) Finally on cancelling we get ,
(1-cos1costhetaθ) / (1+cos1+costhetaθ).......(so L.H.S= R.H.S)........... (Proved)
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I hope this helps :)