# Differentiation Worded Problem Involving Cos

Let y=4cos(x) and x be a function of t such that dx/dt = 3e^(2t) and x = 3/2 when t = 0.

The value of dy/dt when x = ?/2 is: ??

can someone please help - i have no clue how to solve this.

This looks like homework. This forum is focused on the Sage software only. You should post your question at: http://math.stackexchange.com/ You might also find help on using the chain rule by using Paul's notes at: http://tutorial.math.lamar.edu/Classes/CalcI/ChainRule.aspx