^{The funtion f(x)= integration(sin}6^{t +cos}6^{t)dt from 0 to x}3, ^{is increasing in?}

directly differentiate to get

f''(x) = sin⁶x³  + cos⁶x3

then use the fac of a"3 + b"3 formula and equate th expression to zero,

you get the desired range!!

best part of using this newton libnit rule tis that you dont need to integrate the whole function,

direct differentiation is possible!!