Problem with solving 'basic formula' derivatives

[Notlim]

Homework Statement

[PLAIN]http://webwork2.asu.edu/webwork2_files/tmp/equations/9f/ab106661843d52ded597f9bcb68ace1.png find f'(x)

Homework Equations

The Attempt at a Solution

I tried 8x^.5(-4), 0, and a few others once my original try came up with nothing. I realize sqrtx should come out as .5x^-.5, x should be 1 but I'm not sure how to use the 16 and -5 for sure.

I tried a couple others deeper into the assignment and ran into the same problems

Homework Statement

[PLAIN]http://webwork2.asu.edu/webwork2_files/tmp/equations/af/00b3090b142ffad24c374c5457d8701.png

Homework Equations

The Attempt at a Solution

This one i got (12x+12)/(.5x^-.5) which is wrong also.


In addition to helping me with those problems and simple rules that I'm forgetting would be great help. I know i must be missing something amazingly simple. On a side note this is online work that doesn't require you to simplify so I know its not going to be that.

Thanks!

 

[Doc Al]

Are you familiar with the product and quotient rules?

See: http://people.hofstra.edu/stefan_waner/Realworld/tutorials/unit3_1.html

 

[cristo]

How do you think you should try and solve the problems? Have you tried using the product rule?

[Wow, beaten by a split second!]

 

[Notlim]

Thanks so much, got through those problems with a breeze. The problems were under 2.3 while the rules were under 2.4 in our book, so i didn't think to look there.

I have a new problem though;

[PLAIN]http://webwork2.asu.edu/webwork2_files/tmp/equations/d2/30fb1bbeb9b92f7b1e0062bfe44f211.png
I need to find f'(x) in this one also and i went about it by doing the product rule on the left and the quotient rule on the right. This is what i got multiple times:
[PLAIN]http://webwork2.asu.edu/webwork2_files/tmp/equations/59/803e4ab45c0a518b7e25421e0ea89d1.png

 

[Doc Al]

I need to find f'(x) in this one also and i went about it by doing the product rule on the left and the quotient rule on the right. This is what i got multiple times:
[PLAIN]http://webwork2.asu.edu/webwork2_files/tmp/equations/59/803e4ab45c0a518b7e25421e0ea89d1.png[/QUOTE]
The first two terms look fine (though they can be simplified), but that last one needs to be redone. (What did you get for the derivative of the denominator?)

 

[Whitishcube]

what i would do in these situations is combine the exponents in all of these problems.
for example, x^4 times x^0.5 would be x^4.5, or x^(9/2).

doing this is an excellent strategy that allows you to avoid any product or quotient rules, and seeing that these problems are appearing in your book before the chapters on these two rules, i would do it this way instead.