The angle between the pair of lines whose equation is `4x^2+10 x y+m y^2+5x+10 y=0` is `tan^(-1)(3/8)` `tan^(-1)(3/4)` `tan^(-1){2(sqrt(25-4m))/(m+4)},m in R` none of these

Options

A. `tan^(-1)(3//8)`
B. `tan^(-1)(3//4)`
C. `tan^(-1){2sqrt(25-4m//)(m+4)},m in R`
D. None of these

Answer

2

Explanation

Being a pair of lines , `abc+2fgh-af^(2)-ch^(2)=0`. This given m=4 . Now , find the angle between the lines.