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Find the points of intersection for r = 3 + sin(theta) and r = 3 - sin(theta)!!!! PLEASE HELP!?
1. Find the points of intersection for r = 3 + sin(theta) and r = 3 - sin(theta).
PLEASE ANSWER LAST QUESTION
2. find the slope dy/dx of the polar curve r = 2 - 2cos(theta) at the point (r,theta) = (2, pi/2).
2 Answers
- 7 years ago
r = 3 + sin(t)
r = 3 - sin(t)
3 + sin(t) = 3 - sin(t)
2sin(t) = 0
sin(t) = 0
t = pi * k
r = 3 + sin(pi * k)
r = 3
(3 , pi * k) where k is an integer
r = 2 - 2cos(t)
y = r * sin(t)
x = r * cos(t)
r * sin(t) =>
2 * (1 - cos(t)) * sin(t) =>
2sin(t) - sin(2t)
y = 2sin(t) - sin(2t)
dy/dt = 2cos(t) - 2cos(2t)
r * cos(t) =>
2 * (1 - cos(t)) * cos(t) =>
2 * (cos(t) - cos(t)^2) =>
2cos(t) - 2 * (1/2) * (1 + cos(2t)) =>
2cos(t) - 1 - cos(2t)
dx/dt =>
-2sin(t) + 2sin(2t)
dy/dx =>
(dy/dt) / (dx/dt) =>
(2cos(t) - 2cos(2t)) / (2sin(2t) - 2sin(t)) =>
(cos(t) - cos(2t)) / (sin(2t) - sin(t))
t = pi/2
(cos(pi/2) - cos(pi)) / (sin(pi) - sin(pi/2)) =>
(0 - (-1)) / (0 - 1) =>
1/(-1) =>
-1
- SidheswaranLv 47 years ago
1)we can also use polar co ordinate formula to avoid lengthy calculations.
dr /d theta = 0 +2 sin theta ===> dtheta /dr = 1 / 2 sin theta = 1/ 2 * 2 sin( theta /2) cos( theta / 2)