For the curve y = 4x3 – 2x5, find all the points at which the tangent passes through the origin.
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 (x, y) is 12x2 − 10x4.
The equation of the tangent at (x, y) 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
