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

One more trig identity

  • Thread starter chops369
  • Start date
  • #1
56
0

Homework Statement


I'm finally starting to understand proving trig identities, but I have just one more that I can't seem to figure out.

secx - tanxsinx = cosx


Homework Equations


N/A


The Attempt at a Solution


Well first, I multiplied the tanx and sinx and came up with sin2x / cosx
Now I'm stuck. I'm trying to do 1/cosx - sin2x / cosx
Would the GCF be (cosx)(cosx) or just cosx, I'm drawing a blank here. I'm debating whether or not to change the sin2x to 1 - cos2x, but even if I do, I can't figure out how that would simplify to just cosx
 

Answers and Replies

  • #2
Cyosis
Homework Helper
1,495
0
You're almost there[tex]\frac{1}{\cos x}-\frac{\sin^2x}{\cos x}=\frac{1}{\cos x}(1-\sin^2x)[/tex]. You should notice something very familiar now.
 
  • #3
56
0
So would it simplify to cos2x / cosx, which would then simplify to cosx for my answer?
 
  • #4
Cyosis
Homework Helper
1,495
0
Yep it's that easy!
 

Related Threads for: One more trig identity

  • Last Post
Replies
14
Views
2K
  • Last Post
Replies
3
Views
2K
  • Last Post
2
Replies
27
Views
7K
Replies
48
Views
10K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
6
Views
626
  • Last Post
Replies
6
Views
1K
  • Last Post
Replies
7
Views
1K
Top