Evaluate the indefinite integral.

so first i simplified it to ∫(1/4√x²-16)x dx

i took the integral by letting x = 4 secθ, dx= 4secθtanθ

then for √x²-16)= 4tanθ

then i pluged in √x²-16)= 4tanθ and x= 4 secθ for the equation ∫(1/4√x²-16)x dx and my intergral came out to be -1/4cosθ + C but it is wrong i dont get what i have to do next?