Question

Mathematical equation for Involute is ___________

(a) x = a cos^3 θ

(b) x = r cosθ + r θ sinθ

(c) x = (a+b)cosθ – a cos(^a+b⁄a θ)

(d) y = a(1-cosθ)

This question was addressed to me in class test.

Origin of the question is Construction of Involute topic in chapter Geometrical Construction of Engineering Drawing

Answer 1

The correct choice is (b) x = r cosθ + r θ sinθ

The best explanation: x= a cos3 Ɵ is equation for hypocycloid, x= (a+ b) cosƟ – a cos ( (a+b)/aƟ) is equation for  epicycloid, y = a (1-cosƟ) is equation for cycloid and x = r cosƟ + r Ɵ sinƟ is equation for Involute.