# Math Help - Length of a Plane Curve

1. ## Length of a Plane Curve

I'm stuck on this. Any help you can give would be great!

If is given by: and is given by:
Find the total length of the astroid described by and .
(The astroid is the curve swept out by as ranges from to )

2. The formula for arc length can be remembered as

$\int_a^b\sqrt{dx^2+dy^2}=\int_a^b\sqrt{\left(\frac {dx}{dt}\right)^2+\left(\frac{dy}{dt}\right)^2}\,d t.$