Integrating Trigonometric Functions Videos
Video 1: Integrating a product of sines and cosines with an odd power of sines or cosines
This strategy should work for problems 1, 3, 5 and 13
Video 2: Integrating a product of sines and cosines with only even powers
This strategy should work for problem 7
Video 3: Easier versions of integrating secants and tangents: overview
This strategy should work for problems 21, 27, 29
Video 4: Finishing the first example (u = tanx)
Video 5: Finishing the second example (u = secx)
Video 6: Other integrals with secants and tangents
These strategies should work for 23 and 31
Video 7: Part of vid 6: integrating tanx
Hints for the 7.1 problems
Click to show/hide hints for 7.1 # 13
Hint 1: If you let \(u=t\), what would \(dv\) have to be? Can you integrate it?
so v is?
\(dv=\csc^2(t) dt\) so \(v=-cot(t)\)
So then \(uv-\int v du =\)
\(uv-\int v du = -t \cot(t) - \int cot(t)\)
If you know how to integrate tan(t), you should be able to figure out how to integrate cot(t).
Click to show/hide the hint for 7.1 # 29
let \(u=x\) and \( dv=\sin x \cos x dx\)
Then to find v , you need to integrate \(\int \sin x \cos x dx\), which you should now know how to do!
If you did step 1 right, you should get:
Either \( \dfrac{1}{2} x \sin^2(x) - \int \dfrac{1}{2} \sin^2(x) dx\)
OR you might have gotten \( -\dfrac{1}{2} x \cos^2(x) + \int \dfrac{1}{2} \cos^2(x) dx\)
OR, if you are very good with your trig identities, you might have gotten
\( -\dfrac{1}{4} x \cos(2x) + \int \dfrac{1}{2} \cos(2x) dx\)
All of which will give you a correct answer, and after you plug in the endpoints will all give you the same number.