From the differential equation of family of lines situated at a constant distance p from the origin.

Options

A. x+y+2=0
B. x+y+4=0
C. `x "cos" alpha + y "sin" alpha = 2`
D. `x "cos" alpha + y "sin" alpha = (1)/(2)`

Answer

C

Explanation

If normal to the line make an angle `alpha` with x-axis, then equation of line is
`x"cos"alpha+y"sin"alpha = p,` where p is distance of line from origin.
Here, p=2
So, equation of lines is `x"cos"alpha+y"sin"alpha = 2.`