Calculus Volume 2 · free preview

Area and Arc Length in Polar Coordinates

Polar areas integrate one half r squared over the angle, and polar arc length integrates root of r squared plus r prime squared, the circle and cardioid the classic computations.

1. The polar area formula

The polar area formula

2. Area between polar curves

Area between polar curves

3. Polar arc length

Polar arc length

4. Numerical polar lengths

Numerical polar lengths

5. Polar area formula

The area swept by r = f of theta from alpha to beta equals which integral?

6. Circle from polar area

Applying the polar area formula to the constant curve r = a over [0, 2 pi] gives which area?

7. Area between curves integrand

The area between polar curves r_outer and r_inner over [alpha, beta] uses which integrand?

8. Polar arc length integrand

The polar arc length integrand is which expression?

9. Intersections for area ranges

To compute the area inside the cardioid r = 1 + cos theta but outside the circle r = 1, what must be found first?

10. Rose petal area

One petal of r = cos 2 theta has area pi over 8. As a fraction of pi, what is it? Answer like pi/8.

11. Cardioid perimeter

The cardioid r = 1 + cos theta has perimeter 8. As a number, what is it? Answer with a number.

12. Circle derivative term vanishes

For the circle r = a constant, the arc length integrand simplifies because dr/d theta vanishes. What does the integrand become?

13. Area element sector

The infinitesimal polar area element is half r squared d theta. As a two-word name, what shape is it? Answer like small sector.

14. Radial motion contribution

In the arc length integrand, the term (dr/d theta)^2 represents the contribution of which motion? Answer with two words.

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