Help!!!!!

[Guest]

I am trying to find the 17th derivative of f(x)=7sin(x+pi)+cos(2x). I know how to find the 1st and 2nd derivatives, but I don't know where to start with this.

 

[stapel]

You know that the derivatives of sine and cosine cycle back and forth between the two functions. Try taking a few more derivatives, and see if you can find a pattern for this function as well.

Eliz.

 

[pka]

This is a problem in pattern recognition.
Begin by finding the first five or six derivatives.
With any luck, you will begin to see a pattern in the derivatives.
Look for a relation between the ‘number’ of the derivative and the ‘numbers’ in the derivative.