Quandaries
and Queries 

Name: ladymei I have a question about calculus: I used the equation x(dx/dt)y(dy/dt)=A(dA/dt), where t 

Hi, If x is the width of a rectangle and y is its length then the area A is given by
Since the length and width are changing with time you can think of x, y and A as functions of time. Thus,
This is the expression you need to differentiate, with respect to t, to find an expression for the rate at which the area is changing. Differentiation with respect to t gives,
Penny 

