If the gradient of one of the lines `x^(2)+hxy+2y^(2)=0` twice that of the other , then sum of possible values of h ____________.

Options

A. `pm 2`
B. `pm 3`
C. `pm 1`
D. `pm 3//2`

Answer

B

Explanation

Lat m and 2 m be the gradients of the lines given by the equation `x^(2)+hxy+2y^(2)=0`. Then,
`m+2m=-(h)/(2) and 2m^(2)=(1)/(2)`
`rArr" "m=(-h)/(6) and m^(2)=(1)/(4)rArr (h^(2))/(36)=(1)/(4)rArr h= pm3`.