A line passing through the point A(9,0) makes an angle of 30 with the positive direction of x-axis. If this line is rotated about A through an angle of 15 in the clockwise direction, then its equation in the new position is :
- y 3+2+x=9
- x 3+2+y=9
- x 3-2+y=9
- y 3-2+x=9
Answer
(4) y 3-2+x=9
Solution
[figure]
Clockwise rotation reduces the inclination: 30 -15 =15
m= 15 =2- 3
y-0= (2- 3 )(x-9)
y2- 3=x-9 x- y2- 3=9
y 3-2+x=9
Answer: (4)