







r=10cos(t) in cylindrical coordinates 
20130518 

From r.m: question from calculus exam: what is the figure obtained having eqn.r=10cos(t) in cylinderical coordinates?
i know it is a cylinder with center (5,0) ,but can't the equation represent two cylinders ,one with center
(5,0) and the other with center (5,0).
thanks for any help. Answered by Penny Nom. 





Polar coordinates 
20100414 

From Lan: Given the rectangular equation (x^2)+2x+(y^2)+y=0, find the polar equation. Answered by Harley Weston. 





Integration of cos (x^2+y^2) dx dy 
20100212 

From anna: How do you evaluate the integration of integration of cos (x^2+y^2) dx dy? Answered by Tyler Wood. 





Polar coordinates 
20080305 

From kumi: 2.Sketch the graph of r=(2)/(1sinθ). Make sure you show a complete chart demonstrating how you arrive at your sketch, and sketch the graph neatly and clearly with proper labeling.
b. change the equation above to cartesian coordinates and identify the type of graph.
c.explain which coordinate system gives an easier function to graph and why
d.find a function of the form r=f(θ) for a circle centered at (8,π/2) and with the point (0,0) lying on the circle Answered by Penny Nom. 





Three points on the circumference of a circle 
20070730 

From Bharathi: given a circle with radius r and a point x,y on its circumference,output two other
points x1,y1 and x2,y2 on the circle so thar all 3 points form a equilateral triangle. Answered by Stephen La Rocque. 





A complex number in polar form 
20070723 

From roland: write the given complex number z in polar form lzl(p+qi) where lp + qil=1 for 3  4i. Answered by Harley Weston. 





Polar to Cartesian coordinates 
20060115 

From Linden: How do you convert six units at 30 degrees Polar Coordinate into a Cartesian Coordinate? Answered by Penny Nom. 





Converting coordinates 
20041025 

From Allen: I am trying to help my son with his home, but I don't remember these conversions. Please help.
1. Convert the following coordinates
Cartesian x = 7, y = 24
2. Convert the following coordinates
Polar r = 4, theta = pi / 3 Answered by Penny Nom. 





A triangle in the complex plane 
20030710 

From Scott: The vertices O and A of an EQUILATERAL triangle OAB in the complex plane are located at the origin and 3 + 3i. Find all possible values for the complex number representing the vertex B. Give the location of B in both polar and cartesian form (to 2.d.p) Answered by Penny Nom. 





Polar coordinates 
20000224 

From Tran Trung: How do I convert r = 2/(2sin(theta)  3cos(theta)) to rectangular and x^{2} + y^{2} 2y = 0 to polar form? Answered by Harley Weston. 





A valentines project 
20000221 

From Courtney Dohoney: I was assigned a valentines project. Our job is to make a valentines card that has a math theme. On my valentines card I would like to include the set of equations that when graphed look like a heart. If you can figure out a set of equations and get it back to me I would be very happy. Answered by Harley Weston. 





A Polar Plot 
19990506 

From Irene: Consider the polar equation r=23Cos(theta/2) In the interval [o, 4Pi], how would you find the area of one of the leaves and also the length of one of the edges of a leaf? Answered by Harley Weston. 





Complex numbers/polar coordinates 
19990325 

From Kate Cegelis: What is the relationship between complex numbers and polar coordinates? Answered by Harley Weston. 

