Question

if f(x) = cos(x2) then find f '(x)
(A) -6xcos? (x2) sin(x2)
(C)-3xcos (x2)sin(2x2)
(B) 6xcos2 (x2) sin(x2)
(D) -3cos (x4) sin(2x)
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Answer 1

this solved with identity formula 10or11std