A) \[(x-1)\,cos\,(3x+4)\]
B) \[\sin \,(3x+4)\]
C) \[\sin \,(3x+4)+3(x-1)\,cos\,(3x+4)\]
D) None of these
Correct Answer: C
Solution :
\[ATQ\int_{1}^{b}{f(x)dx=(b-1)sin(3b+4)}\] Differentiating both sides w.r.t.b we get\[f(b)=3\left( b-1 \right)\cos \left( 3b+4 \right)+\sin \left( 3b+4 \right)\]\[\Rightarrow f(x)=3(x-1)cos(3x+4)+\sin \left( 3x+4 \right)\]You need to login to perform this action.
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