<s>[INST] Simplifying $ 2\cos^2(x)\sin^2(x) + \cos^4(x) + \sin^4(x)$ who can simplify the following term in a simplest way?
$$ 2\cos^2(x)\sin^2(x) + \cos^4(x) + \sin^4(x)$$
(The answer is 1). Thanks for any suggestions.
 [/INST] HINT : 
$$2ab+a^2+b^2=(a+b)^2$$
with
$$\cos^2 (x)+\sin^2(x)=1.$$
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