Trig Sub Basics
Recognizing forms
Evaluate
After substitution
Challenge problems
100

This is the purpose of trigonometric substitution in integration.

What is to simplify integrals involving square roots of quadratic expressions?

100

Identify the correct trig sub for ∫ dx / √(4 - x²)

What is x = 2sin(θ)?

100

Evaluate: ∫ dx / √(1 - x²)

What is arcsin(x) + C?

100

After substituting x = a*sin(θ), what does √(a² - x²) become?

What is a*cos(θ)?

100

Evaluate: ∫ dx / (x² + 4)^(3/2)

What is x / (4√(x² + 4)) + C

200

If the integrand has √(a² - x²), this trig function is used for substitution.

What is sin(θ)?

200

Choose the right trig sub: ∫ dx / √(x² + 9)

What is x = 3tan(θ)?

200

Evaluate using trig sub: ∫ dx / √(4 + x²)

What is sinh⁻¹(x/2) + C or ln

200

After substituting x = a*tan(θ), what does dx become?

What is a*sec²(θ)dθ?

200

Evaluate: ∫ dx / (x√(x² - 9))

What is (1/3)arcsec(

300

Trig sub is most useful when the integrand contains this type of expression.

What is a square root of a quadratic expression?

300

Choose the substitution for ∫ dx / √(x² - 1)

What is x = sec(θ)?

300

Use trig sub to evaluate: ∫ x / √(x² + 9) dx

What is √(x² + 9) + C

300

What is the integral of sec³(θ)?

What is (1/2)sec(θ)tan(θ) + (1/2)ln

300

Evaluate: ∫ x³ / √(x² + 1) dx

What is (1/3)(x² - 2)√(x² + 1) + C

400

True or False: Trig substitution can be used for rational functions.

What is False?

400

What identity justifies x = a*sin(θ) when integrating √(a² - x²)?

What is sin²(θ) + cos²(θ) = 1?

400

Solve using trig sub: ∫ dx / (x²√(x² - 4))

What is (1/4) * sec⁻¹(

400

After integrating, how do you go back from θ to x?

What is using a right triangle based on the trig substitution?

400

Solve: ∫ x² / √(9 - x²) dx

What is (1/2)x√(9 - x²) + (9/2)arcsin(x/3) + C

500

Complete the substitution: x = a * tan(θ) implies dx = __.

What is a * sec²(θ) dθ?

500

Choose the substitution for ∫ x² / √(x² + 16) dx

What is x = 4tan(θ)?

500

Evaluate: ∫ x² / √(x² + 1) dx

What is (1/2)x√(x² + 1) - (1/2)ln

500

With x = 3tan(θ), what is tan(θ) in terms of x?

What is x/3?

500

Evaluate: ∫ √(x² - 16) / x dx

What is √(x² - 16) - 4ln