1. R

    3.14 vs. 3.141.../irrational pi for a circle

    I realize math can be used for abstraction... Would using irrational pi for a circle other than 3.14 make the circle more eliptical? Why use the irrational number for a circle, instead of 3.14, if the irrational size for a circle cannot even exist in reality? why use it for a circle?
  2. J

    CALC 3 Hyperbolas, Parabolas, and elipse

    Need help with 3 questions. 1.) A parabola has a vertex at (-2,3) and its directrix is the line y=5. Write an equation of the parabola and find its focus and axis of symmetry. I thought p = 3 , because its the difference between the y coordinate and the directrix. Then I plugged the vertex...
  3. M

    question on the volume of a pool in the shape of an elipse

    As viewed from above, a swimming pool has the shape of the ellipse x^2/25 +y^2/16=1 The cross sections perpendicular to the ground and parallel to the y-axis are squares. Find the total volume of the pool. (Assume the units of length and area are meters and square meters respectively.)
  4. S

    Two points on an elipse; trying to find foci and vertex/minor axis

    Hi there new here. This seems like a really easy question but can't get it: basically standard form of ellipse: x2 y2 -- + -- = 1 a2 b2 Here's the question: ''pass through (2,2) and (1,4)'' plz solve, thanks! (what I did: filled in two of these equations with this info on top and...
  5. L

    Integral of an Elipse

    Hi... again :p I need to calculate the VOLUME of an elipse, but I have no idea how to do it... I assume it would require integration though. The cross-sectional function for my elipse is: \sqrt{((1-(x-4)^2)/16)*9} ; 0<=x<=6 and -\sqrt{((1-(x-4)^2)/16)*9} ; 0<=x<=6 which gives: So...
  6. S

    cylindrical geometry question

    Hi, Here is my challenge to you: I have a cylinder with its axis of rotation on the x axis and of radius r. I cut the cylinder with two planes both perpenticular to the y-x plane and passing through the origin: one at 45 degree from the x axis and one at 135 degree. I understand that I...
  7. M

    Hyperbola and Elipse Equations

    Need help with these...or more like I forget algebra. 4y^2 - x^2 = 1 4y^2 + x^2 = 1 Thanks.
  8. B

    "walk" on elipse

    I'm not shure if this is university level, but here goes. I have an elipse, and an arbitrary point on it. What I want is to walk a specific distance along the elipse, from the givin point, and then get the point at that location. Anyone here got a formula for that?
  9. E

    HELPPPPP!!! Hyperpola and Ellipse word problem

    (1) A hyperbolic reflector for a radiotelescope has the equation : y^2/900-x^2/225=1. If the reflector has a diameter of 20 feet, how deep is it (in feet)? (2)A nuclear cooling tower is in the shape of a hyperboloid(that is, a hyperbola rotated around its conjugate axis). The equation of the...
  10. K

    Basic Conics Help (elipse)

    Given the length of the semi-major axis, and the distance between the 2 focus, how can I find the length of the semi-minor axis?
  11. bdj

    line tangent to an elipse given one point

    Write the equations of the tangent lines from (3,0) to x^2 + 2y^2 = 6 Anyone have any idea? I've graphed it but i still have no clue where it's tangent to the elipse. -bdj