Calculus II · Techniques of Integration
Trigonometric Integrals — Practice Problems and Worked Solutions
Power identities turn trig products into integrable forms.
The formulas you need here
Power-reduction identities
- What it says
- An even power of sine or cosine trades itself for a single cosine of double the angle.
- When to reach for it
- Even powers of sine or cosine, where no substitution presents itself.
- Watch out
- Only the cosine version carries the plus sign. Getting them the wrong way round flips the answer.
The identity turned an unintegrable square into two standard terms.
Odd trig powers
- What it says
- Split off one factor to become du, and convert everything else to the other function.
- When to reach for it
- At least one of the two powers is odd.
- Watch out
- Peel from the odd one. Peeling from the even power leaves you with a square root you cannot substitute.
u = cos x, and the peeled sin x supplied the du.
16 worked problems
Every step is generated and checked by a computer algebra system.
- 1.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 2.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 3.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 4.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 5.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 6.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 7.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 8.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 9.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 10.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 11.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 12.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 13.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 14.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 15.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution
- 16.
Evaluate the trigonometric integral.
Answer:
Step-by-step solution