• Support PF! Buy your school textbooks, materials and every day products Here!

How to solve the equation with square roots

  • #1

Homework Statement


I am having trouble to find out what rule to use when solving this equation:
y=5x^2 square root of (2x^3)/15x^7 square root x

How do you right square roots on the keyboard. As you can see I am quit new to this forum


Homework Equations


I have tried to use the chain rule and the quotiant rule. But when I use a different rule I get a different answer.



The Attempt at a Solution

 

Answers and Replies

  • #2
290
2


Is this the correct equation? (you can see the markup by quoting me)

[tex]y=5x^2 \sqrt{\frac{2x^3}{15x^7}\sqrt{x}}[/tex]
 
  • #3


No
I think it is [tex]y=5x^2 {sqrt{2x^3}}\15x^7{sqrt{x}}[/tex]
 
  • #4


This is what I mean sorry for that

[tex]y=5x^2\sqrt{2x^3}{frac{15x^7}\sqrt{x}} tex][/QUOTE]
 
  • #5
290
2


[tex]y=5x^2\sqrt{2x^3}{\frac{15x^7}{\sqrt{x}} [/tex]
You can differentiate x to a fractional powers the same way you can differentiate x to an integral power. Try simplifying it first.
 
  • #6


Thanks anyway I cann't get the question right. The 5x^2 and sqrt(2x^3) are on the top
and 15x^7 and sqrt(x) are on the bottom. lets try that.
 
  • #7
HallsofIvy
Science Advisor
Homework Helper
41,791
919


So
[tex]\frac{5x^2\sqrt{2x^3}}{15x^7\sqrt{x}}[/tex]?
As qntty suggested, you can write the square root as a fractional power: [itex]\sqrt{x}= x^{1/2}[/itex].

Your expression is
[tex]\frac{5\sqrt{2}x^2x^{3/2}}{15x^7x^{1/2}}= \frac{5\sqrt{2}x^{2+3/2}}{15x^{7+ 1/2}}= \frac{5\sqrt{2}x^{7/2}}{15x^{15/2}}[/tex]
[tex]= \frac{\sqrt{2}}{3}x^{7/2}x^{-15/2}= \frac{\sqrt{2}}{3}x^{-4}[/tex]
That should be easy to differentiate.
 
Last edited by a moderator:
  • #8


Thank you very much. Can you just tell me what rule you used, so I can apply it to other equations.
 
  • #9
HallsofIvy
Science Advisor
Homework Helper
41,791
919


I used a number of "rules". I used the fact that [itex]\sqrt{x}= x^{1/2}[/itex], I used the laws of exponents to reduce the problem to a single power of x, and I used the power rule to differentiate.
 

Related Threads for: How to solve the equation with square roots

Replies
9
Views
4K
  • Last Post
Replies
2
Views
926
Replies
4
Views
647
Replies
3
Views
3K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
5
Views
2K
Replies
3
Views
1K
Replies
22
Views
4K
Top