# Parametrization

Parametrization is a technique in calculus for expressing multiple variables in terms of only one variable, which is usually depicted as "t", over a specified range.

The most common parametrization is for a circle centered at the origin in the xy-plane:

• x = rcos(t)
• y = rsin(t)
• z = 0
• $0 \le t \le \pi$

Always remember to be precise in determining the new limits on the new parameter t.

This technique is particularly useful for calculating extrema and line integrals.