How do you perform multiplication and use the fundamental identities to simplify $(3-3sinx)(3+3sinx)$ ?

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Answer 1 · 2017-09-28T20:46:14

Answer $=9cos^2x$

$(a+b)(a-b)=a^2-b^2$
Here, $a=3$ & $b=3sinx$
$:.(3-3sinx)(3+3sinx)=(3^2-3^2sin^2x)=9-9sin^2x$
$=9(1-sin^2x)=9cos^2x$

How do you perform multiplication and use the fundamental identities to simplify (3-3sinx)(3+3sinx)(3-3sinx)(3+3sinx)?