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

Integrals of Trigonometric Functions

  • Thread starter recon_ind
  • Start date
1. The problem statement, all variables and given/known data

I have three problems that I'm having a hard time with. I'd appreciate any help with
any of the three problems.

[tex]\int((cos(x))^6)dx[/tex]

AND

[tex]\int(x^3 * sqrt(x^2 - 1)[/tex]

AND

Solve for y (separation of variables):
dy/dx = ((2y + 3)^2)/((4x + 5)^2)


2. Relevant equations

Separation of variables for 3rd problem.


3. The attempt at a solution

I have work on scartch paper but I get stuck.
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution
 
867
0
For the first integral, use the reduction formula for cosine.

For the second, try u = x2

For the third, did you try getting everything with y on one side and everything with x on the other?
 
thank you. im going to try this right now. for the third i got down to an integral that would need partial fraction decomposition but got stuck. :(
 
I finally got the first one. so just the 2nd and 3rd problems now.
 

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