Q.

limxπ2(1(x-π2)2x3(π2)3cos(t1/3)dt) is equal to            [2024]

1  3π24  
2 3π28  
3 3π8  
4 3π4  

Ans.

(2)

Let I=limxπ2(1(x-π2)2x3(π2)3cos(t1/3)dt) (00form)

By Leibnitz theorem,

ddxh(x)g(x)f(t)dt=f(g(x))×g'(x)-f(h(x))×h'(x)

    By applying L'Hospital rule, we get

I=limxπ2(-cosx(3x2)2(x-π2))

=limxπ2(3x2sinx-6xcosx2)  (Applying L'Hospital rule)

=3π28