Question
Question: The equation of the tangent to the circle, given by $x = 5 \cos \theta, y = 5 \sin \theta$ at the po...
The equation of the tangent to the circle, given by x=5cosθ,y=5sinθ at the point θ=3π on it, is

A
x−3y=−5
B
x+3y=10
C
3x+y=53
D
3x−y=0
Answer
x + √3y = 10
Explanation
Solution
For a circle with parametric equations
x=5cosθ,y=5sinθ,
the equation of the tangent at the point corresponding to θ is given by:
xcosθ+ysinθ=5.
At θ=3π, we have:
cos3π=21,sin3π=23.
Substitute these into the tangent equation:
x(21)+y(23)=5.
Multiply through by 2 to eliminate fractions:
x+3y=10.
This corresponds to Option B.