How do you differentiate this?

[Dr. HappyNuke]

Here's the problem:

Differentiate: http://www.webassign.net/www31/symImages/9/b/f70b139b79e8157ad26bf9782128ae.gif

I tried this and somehow came up with 7(x^3/2) - 8(x^1/2). But that is not correct.

How do you do this? I really appreciate your help. Thanks.

 

[Matty R]

I applied the Product Rule and got this :

7.Sqrt[x] + (7x - 8)/(2.Sqrt[x])

 

[Pomico]

7(x^3/2) - 8(x^1/2) is just from multiplying out the bracket, you haven't actually differentiated it yet. See if you get the right answer when differentiating what you already have :)

 

[Dr. HappyNuke]

omg you're right...I feel so stupid. >< I shouldn't have taken calc over the summer! lol

 

[Pomico]

Don't worry, I have moments like that far too often. Good luck!