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

Trouble remembering integration

  • Thread starter LocationX
  • Start date
147
0
Hi, I'm having trouble remembering integration...

[tex]\int cos(60 \pi x) [/tex]

this becomes... sin(60 pi x)/60 pi?
 

jamesrc

Science Advisor
Gold Member
476
1
Yes, that's correct... plus a constant if you're looking for the indefinite integral.
 

quasar987

Science Advisor
Homework Helper
Gold Member
4,771
7
Basically, if you remember derivation, there is nothing to remember about integration except that it is the inverse of derivation. If you doubt that the integral of cos(60x) is sin(60x)/60, just verify that the derivative of sin(60x)/60 is cos(60x).
 
integration of cos...

Yes it's ok. Remember how to derive sin and cos and it will surely be easier for you
 
732
0
Just remember that nice substitution rule...
[tex] \int {\cos \left( {60\pi x} \right)dx} = \frac{1}{{60\pi }}\int {\cos \left( 60\pi x \right)d\left( {60\pi x} \right)} = \boxed{\frac{{\sin \left( {60\pi x} \right)}}{{60\pi }} + C} [/tex]

...and check via derivative (chain rule here) :smile:
[tex] \frac{d}{{dx}}\left[ {\frac{{\sin \left( {60\pi x} \right)}}{{60\pi }} + C} \right] = \frac{{\cos \left( {60\pi x} \right) \cdot 60\pi }}{{60\pi }} = \cos \left( {60\pi x} \right) [/tex]
 

Related Threads for: Trouble remembering integration

  • Posted
Replies
5
Views
1K
  • Posted
Replies
5
Views
1K
  • Posted
Replies
4
Views
1K
  • Posted
Replies
4
Views
1K
Replies
1
Views
817
Replies
4
Views
2K
Replies
4
Views
1K
Replies
1
Views
6K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top