How Fast is the Area of an Equilateral Triangle Changing?

[Peppy]

I need help with the question: The height h of an equilateral triangle is increasing at a rate of 3cm/min. How fast is the area changing when h is 5 cm.

 

[dextercioby]

What's the area?What's the height?Can u write the former as a function of the latter?

Daniel.

 

[James R]

You want dA/dt. Use the chain rule:

\frac{dA}{dt} = \frac{dA}{dh} \frac{dh}{dt}

Of course, you'll need to work out what the two derivatives on the right are.