Question 401384
Btw, it's spelled "verify," not "vertify." I can immediately determine who wrote each problem based on the spelling...


Anyway, we can write {{{4*sin^2(x)cos^2(x)}}} as {{{(2*sin(x)cos(x))^2}}}. Applying double-angle formula for sine, this is equal to {{{sin^2(2x)}}}. Therefore the expression is equal to 


{{{cos^2(2x) + sin^2(2x)}}}, which is equal to 1 by the Pythagorean identity.