Integrate the following functions `sqrt(1+x^2/9)`

Explanation

`int sqrt(1+x^2/9) dx = int sqrt(1+(x/3)^2) dx`
1/(1/3)[(x/3)/2 sqrt(1+(x/3)^2) + 1/2 log|x/3 + sqrt(1+(x/2)^2)|]+c`
`3[x/6 sqrt(1+x^2/9) + 1/2 log|x/3 + sqrt(1+x^2/9)|]+c`