SOLUTION: Vertify is an identity cos^2(2x)+4sin^2(x).cos^2(x)=1

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Question 401384: Vertify is an identity
cos^2(2x)+4sin^2(x).cos^2(x)=1

Found 2 solutions by Tatiana_Stebko, richard1234:
Answer by Tatiana_Stebko(1539)   (Show Source): You can put this solution on YOUR website!


Use FORMULA

Use FORMULA , so


Answer by richard1234(7193)   (Show Source): You can put this solution on YOUR website!
Btw, it's spelled "verify," not "vertify." I can immediately determine who wrote each problem based on the spelling...

Anyway, we can write as . Applying double-angle formula for sine, this is equal to . Therefore the expression is equal to

, which is equal to 1 by the Pythagorean identity.

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