Question

Direction cosines of line `(1-x)/0=y=z` are:

Options

• 1, 1, 1

• `0,(-1)/sqrt2,(-1)/sqrt2`

• 1, 0, 0

• 0, –1, –1

Answer 1

`bb(0,(-1)/sqrt2,(-1)/sqrt2)`

Explanation:

`(x-x_1)/a=(y-y_1)/b=(z-z_1)/c`

`(x-1)/0=(y-0)/1=(z-0)/1`

Direction ratio (a, b, c) = 0, 1, 1

= `0/sqrt(1^2+1^2),±1/sqrt2,±1/sqrt2`

= `0,(-1)/sqrt2,(-1)/sqrt2`