Evaluate: `tan^(-1)(tan((5pi)/6))+cos^(-1){cos(((13pi)/6))}`

Explanation

`tan^(-1)(tan((5pi)/6))+cos^(-1){cos((13pi)/6)}`

`tan((5pi)/6)=-tan(pi/6)`

`=-1/(sqrt3)`

`cos((13 pi)/6)=cos(pi/6)`

`=sqrt3/2`

`tan^(-1)(-1/sqrt3)+cos^(-1)(sqrt3/2)`

`=-pi/6+pi/6=>0`