`int _``(3x)/(1+2x^(4))`dx

Explanation

`int(3x)/(1+2x^(4))dx`
`=(3)/(4)int(2x)/((1)/(2)+(x^(2))^(2))dx" " {:("माना "x^(2)=t),(rArr 2xdx=dt):}`
`=(3)/(4)int(1)/(((1)/(sqrt2))^(2)+t^(2))dt`
`=(3)/(4)int(1)/(1//sqrt2)tan^(-1)((1)/(1//sqrt2))+c`
`=(3)/(2sqrt2)tan^(-1)(sqrt2x^(2))+c`