Question

Find the equation of a straight line which cuts off an intercept of 5 units on negative direction of y-axis and makes an angle `120^0` with the positive direction of x-axis.

Answer 1

We know that the equation of a line with the slope m and y-intercept c is given by y=mc+c

Here, `m=tan 120^(@)=tan(180^(@)-60^(@))=-tan60^(@)=-sqrt3 and c=-4`
Hence, the required equation of the line is
`y=-sqrt3x-4 Rightarrow sqrt3x+y+4=0 " "[therefore y=mx+c]`