A straight line makes an angle of 30° with the positive x-axis and cuts the y-axis at y = 5. Find the equation of the straight line.
- y = (x/10) + 5
- y = x + 5
- √3y = - x + 5√3
-
√3y = x + 5√3
The correct answer is: D
Explanation
Cos 30 = 5/xx cos 30 = 5, => x = 5√3
Coordinates of P = -5, 3, 0
Coordinates of Q = 0, 5
Gradient of PQ = (y2 - y1)
= 5/5√3 = 1/√3
Equation of PQ = y - y1 = m (x -x1)
y - 0 = 1/√3 (x -(-5√3))
Thus: √3y = x + 5√3
There is an explanation video available .