Given, x = a (cos t + t sin t) and y = (sin t – t cos t)

To find we need to find out and

So, and

x = a (cos t + t sin t)

Differentiating with respect to t.

⇒

⇒

y = a (sin t – t cos t)

Differentiating with respect to t.

⇒

∴

Differentiating dy/dx with respect to t

And

⇒

∴