Question
Class 12MathematicsApplication of Derivatives

For the curve y = 4x3 – 2x5, find all the points at which the tangent passes through the origin. 

Verified Answer

The equation of the given curve is y = 4x3 − 2x5.

⇒ 8cosθ + 4 = 4 + cos²θ + 4 cosθ 

Therefore, the slope of the tangent at a point (xy) is 12x2 − 10x4.

The equation of the tangent at (xy) is given by,

⇒ cos²θ  - 4 cosθ  = 0…………(1)

When the tangent passes through the origin (0, 0), then X = Y = 0.

Therefore, equation (1) reduces to:

⇒ cosθ  (cosθ  - 4) = 0

⇒ cosθ  = 0 or cosθ  = 4

Uploaded image