## ammu123 one year ago evaluate the integral (integral sign) cos x dx/ 1+8 sinx

1. geerky42

Use U-Substitution. Let u = 1+8sinx.

2. ammu123

can u explain how to do it please.

3. sami-21

let t=1+8sin(x) then dt=8cos(x)dx 1/8dt=cos(x)dx integral becomes $\Large \frac{1}{8}\int\limits_{}^{} \frac{1}{t}dt$ you may know that formula that $\Large \int\limits_{}^{} \frac{1}{x}dx =\ln(x)+C$ use this to evaluate hte above integral then substitute back t=1+8sin(x)