The equation of the circle is (x-cosa) ^ 2 + (y-sina) ^ 2 = 1 / 2. When a changes from 0 to 2 π, the area swept by the moving circle is 3Q .
The area swept by the moving circle is a ring, the radius of outer ring is 1 + √ 2 / 2, the radius of inner ring is 1 - √ 2 / 2, area = π * [(1 + √ 2 / 2) ^ 2 - (1 - √ 2 / 2) ^ 2] = 2 √ 2 π
RELATED INFORMATIONS
- 1. If the equation x ^ 2sina-y ^ 2cosa = 1 for X, y denotes an ellipse, then which quadrant is the center of the circle (x + Sina) ^ 2 + (y + COSA) ^ 2 = 9?
- 2. Let a belong to (0, π / 2), and the equation x ^ 2 / Sina + y ^ 2 / cosa = 1 denotes an ellipse with focus on the x-axis, then a belongs to
- 3. How does Sina / (1 + COSA) turn into Tan (A / 2)?
- 4. Given the point m (COSA, Sina), in the plane region represented by the inequality system x-y-1 ≤ 0, x + Y-1 ≤ 0, then the maximum and minimum values of the distance from the point m to the line 6x-y-4 = 0 are m, n respectively, then m-2n is equal to
- 5. Given a = {(x, y) | x = √ 2 cosa, y = √ 2 Sina + m, a is a parameter} B = {{x, y) | x = t + 3, y = 3-T, t is a parameter} and a ∩ B ≠ & # 8709;, the value range of real number m is obtained
- 6. 0°
- 7. Whether there is a, so that sina + cosa = 3 / 2
- 8. When the fractional equation x-1x-3xx-1 + 1 = 0 is solved by the substitution method, if x-1x = y, the original equation is transformed into an integral equation about y, then the integral equation is () A. y2+y-3=0B. y2-3y+1=0C. 3y2-y+1=0D. 3y2-y-1=0
- 9. Through a point P (7,0), the tangent length of the direction circle x square + y square - 4x-5 = 0 is?
- 10. How many lines are there that are tangent to the square of circle C: x + (y + 5) and have equal intercept on two coordinate axes? How many lines are there that are tangent to the square of circle C: x + (y + 5) and have equal intercept on two coordinate axes?
- 11. It is known that the minimum positive period of the function f (x) = 2Sin (ω X - π / 6) sin (ω x + π / 3) (where ω is a normal number and X ∈ R) is π (1) Finding the value of ω (2) In △ ABC, if a < B and f (a) = f (b) = 1 / 2, find BC / ab
- 12. Given the function f (x) = 2Sin (3x + θ), X belongs to [2 α - 5 π, 3 α] and is an odd function, where θ belongs to (0,2 π), what is the value of α - θ? Please write down the specific process of solving the problem,
- 13. A problem of function f (x) = 2Sin π / 3x If the image f (x) = 2Sin π / 3x is shifted one unit image to the left, and then two units to the top, the image obtained is symmetric to the image y = g (x) with respect to x = 1, and G (x) is obtained
- 14. The minimum positive period of function y = 1 / 2Sin & sup2; 3x No,
- 15. The period of sine function y = 3 / 2Sin (3x Pai / 6) Hurry!
- 16. The minimum positive period of the function y = 2Sin (1 / 3x + tt / 6) is
- 17. Why is the minimum positive period of function y = - 2Sin (3x - π / 3) 2 π / 3
- 18. The minimum positive period of the function f (x) = 2Sin ^ 2 (Wx) + 2 radical 3sinwxsin (π / 2-wx) (w > 0) is known to be PI ① Finding monotone increasing interval and symmetric central coordinate of function f (x) ② Find the value range of function f (x) in the interval [0,2 π / 3]
- 19. Increase the radius of the small round site by 5m to get a large round site, double the site area, and calculate the radius of the small round site?
- 20. As shown in the figure, the radius of the small round field is increased by 5m to get the large round field. If the area of the field is doubled, the radius of the small round field is reduced=______ .