I think it's D. The area of A is k2 times the area of rectangle B
Answer:
see explanation
Step-by-step explanation:
Differentiate using the product rule
Given y = f(x)g(x), then
= f(x). g'(x) + g(x). f'(x)
here f(x) =
⇒ f'(x) = 
g(x) = cosx ⇒ g'(x) = - sinx
Hence
=
(- sinx) + cosx 
=
cosx -
sinx
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