Table of contents

0. Functions7h 52m
1. Limits and Continuity2h 2m
2. Intro to Derivatives1h 33m
3. Techniques of Differentiation3h 18m
4. Applications of Derivatives2h 38m
5. Graphical Applications of Derivatives6h 2m
6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
7. Antiderivatives & Indefinite Integrals1h 26m
8. Definite Integrals4h 44m
9. Graphical Applications of Integrals2h 27m
- Area Between Curves
  1h 18m
- Introduction to Volume & Disk Method
  1h 8m
10. Physics Applications of Integrals 3h 16m
- Kinematics
  1h 13m
- Work
  2h 3m
11. Integrals of Inverse, Exponential, & Logarithmic Functions2h 34m
12. Techniques of Integration7h 39m
13. Intro to Differential Equations2h 55m
14. Sequences & Series5h 36m
15. Power Series2h 19m
- Introduction to Power Series
  1h 9m
- Taylor Series & Taylor Polynomials
  1h 10m
16. Parametric Equations & Polar Coordinates7h 58m

7. Antiderivatives & Indefinite Integrals

Integrals of Trig Functions

Calculus

7. Antiderivatives & Indefinite Integrals

Integrals of Trig Functions

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Multiple Choice

Evaluate the integral: $\int_{0}^{\frac{π}{2}} 3 \cos^{2} (x) d x$ .

\frac{3 π}{2}

\frac{3}{2}

\frac{π}{2}

\frac{3 π}{4}

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Verified step by step guidance

Step 1: Recognize that the integral involves the square of a trigonometric function, $ \cos^2(x) $. Use the trigonometric identity $ \cos^2(x) = \frac{1 + \cos(2x)}{2} $ to simplify the integrand. Rewrite the integral as $ \int_0^{\pi/2} 3 \cos^2(x) \, dx = \int_0^{\pi/2} 3 \cdot \frac{1 + \cos(2x)}{2} \, dx $.

Step 2: Factor out the constant $ \frac{3}{2} $ from the integral. This gives $ \frac{3}{2} \int_0^{\pi/2} (1 + \cos(2x)) \, dx $. Split the integral into two separate integrals: $ \frac{3}{2} \left[ \int_0^{\pi/2} 1 \, dx + \int_0^{\pi/2} \cos(2x) \, dx \right] $.

Step 3: Evaluate the first integral, $ \int_0^{\pi/2} 1 \, dx $. The integral of 1 with respect to $ x $ is $ x $, so this becomes $ x \big|_0^{\pi/2} = \pi/2 - 0 = \pi/2 $.

Step 4: Evaluate the second integral, $ \int_0^{\pi/2} \cos(2x) \, dx $. The integral of $ \cos(2x) $ is $ \frac{1}{2} \sin(2x) $, so this becomes $ \frac{1}{2} \sin(2x) \big|_0^{\pi/2} = \frac{1}{2} [\sin(\pi) - \sin(0)] = \frac{1}{2} [0 - 0] = 0 $.

Step 5: Combine the results of the two integrals. The first integral contributes $ \pi/2 $, and the second integral contributes 0. Multiply the sum by $ \frac{3}{2} $: $ \frac{3}{2} \cdot (\pi/2 + 0) = \frac{3\pi}{4} $.