Register to reply 
Derivativesby courtrigrad
Tags: derivatives 
Share this thread: 
#1
Oct505, 07:23 PM

P: 1,237

Suppose [tex] f(x) = \frac{(x3)^{4}}{x^{2}+2x} [/tex]. Find the derivative an determine the values for which it is equal to 0. So [tex] f'(x) = \frac{x^{2}+2x(4(x3)^{3})  (x3)^{4}(2x+2)}{(x^{2}+2x)^{2}} [/tex]. But now how would I go about finding the values for which the derivative equals 0? [tex] f'(x) = \frac{x^{2}+2x(4(x3)^{3}) (x3)^{4}(2x+2)}{(x^{2}+2x)^{2}} = 0 [/tex]. Is it possible to factor?
Thanks 


#2
Oct505, 07:53 PM

P: 788

For any fraction, let's call it [itex]\frac{A}{B}[/itex], which part will make the whole thing equal to 0? A or B?



#3
Oct505, 08:08 PM

P: 1,237

A
will yeah 


#5
Oct605, 03:32 AM

HW Helper
P: 1,024

Your derivative isn't correct yet, make sure you check that first!



#6
Oct605, 08:16 AM

Math
Emeritus
Sci Advisor
Thanks
PF Gold
P: 39,297

The derivative is correct, assuming that the missing parentheses BobG mentions is put in correctly!



Register to reply 
Related Discussions  
Line Tangent ro a Parabola  Precalculus Mathematics Homework  5  
When to use derivatives?  Calculus  8  
Derivatives  Calculus & Beyond Homework  0  
3 different derivatives?  Calculus & Beyond Homework  12  
Find instantaneous rate of change of 7/3z^2  Calculus & Beyond Homework  2 