Question 1026392
What if instead of showing the steps, you are told two things:


Difference of Squares,
Pythagorean Trigonometric Identity.



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Better if you actually try.
Observe the two factors that the product will give the Difference of two Squares.  You will then make use of the very basic trigonometry identity, {{{cos^2(x)+sin^2(x)=1}}}.