SOLUTION: using double angle formula prove a) sin^ 2 2x( cot^2 x-tan^2 x)= 4cos 2x very complicated question plz help thx lots

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Question 1120469: using double angle formula
prove
a) sin^ 2 2x( cot^2 x-tan^2 x)= 4cos 2x
very complicated question plz help
thx lots
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Not complicated at all, actually.



Double angle formula for sine:



tangent is sine over cosine and cotangent is the reciprocal of tangent:



Apply common denominator:



Square the first factor:



Eliminate factors common to numerator and denominator:



Apply double angle identity for cosine:



Q.E.D.


John

My calculator said it, I believe it, that settles it