Question

Question #62e23

Answer 1

`(1+tanx)/(1-tanx)=(tan(pi/4)+tanx)/(1-tan(pi/4)tanx)=tan(pi/4+x)`

`d/dx((1+tanx)/(1-tanx))`
`=d/dx(tan(pi/4+x))`
`=sec^2(pi/4+x)`