Question

Evaluate the integral.

Answer 1

D

Explanation:

`\int\limits^4_1 {(7^(lnx))/(x) } \, dx \\put~ln~x=y\\diff.\\(1)/(x) dx=dy\\when~x=1,y=ln1=0\\when x=4,y=ln~4\\\int\limits^(ln4)_0 {7^y} \, dy\\=(7^y)/(ln7) |0 ~\rightarrow~ ln 4\\= (7^(ln4))/(7)`