The Goal

Find

The Mistake

Find the mistake:

(Roll the mouse over the math to see a hint in red)

The Correction

(Roll the mouse over the area above to see the correction in blue)

An Explanation

The derivative of 1 (with respect to t) is 0, not 1.

(The student may have hurried past the derivative of 1 to do the derivative of cos(t); take care with all parts of a problem.)