What rate is x^4 increasing when x=4?

[adanthuis]

If x is positive and increasing at a rate of 2 units per second, at what rate is x^4 increasing when x=4?

I don't even know how to start.
If you can help me I would be greatful.

 

[Dick]

If x is increasing at the rate of 2 units/second then it must be increasing wrt some variable, call it t. So you are given dx(t)/dt=2 and x(t)=4. Now take the derivative of x(t)^4 and don't forget the chain rule.

 

[adanthuis]

duh stupid me I know what to do thank you anyway