If `p` is the length of perpendicular from point `(1,1)` to the straight line `ax+by+a+b=0`, then prove that :
`p^(2)=4+(8ab)/(a^(2)+b^(2))`

Explanation

Length of perpendicular from point `(1,1)` to the line `ax+by+a+b=0` is
`p=(a+b+(a+b))/(sqrt(a^(2)+b^(2)))=(2(a+b))/(sqrt(a^(2)+b^(2)))`
`implies p^(2)=(4(a+b)^(2))/(a^(2)+b^(2))=(4(a^(2)+b^(2))+8ab)/(a^(2)+b^(2))`
`=4+(8ab)/(a^(2)+b^(2))`