Trying to understand the question: Find dy/dx

  • Thread starter Thread starter ugeous
  • Start date Start date
ugeous
Messages
23
Reaction score
0
Hello!

Question asks: Find dy/dx. Do not simplify.

y = sec(cube root x)

My answer is

dy/dx = sec(cube root x) * tan(cube root x)

Am I correct?

thanks!
 
Physics news on Phys.org
Hello ugeous. You are VERY close. Remember the chain rule? Our inside angle for sec in y = sec (cube root x) is cube root x. you must take the derivative of this "inside angle" to complete the problem correctly.
 
Oh, right!

sec(cube root x) * tan(cube root x) * 1/3(x^-2/3)

Is this correct?
 
You bet you :)
 
Thanks man!
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top