MATH--Please help!!

posted by .

I'm desperate!

Find the point where the curve r(t)=(12sint)i - 12(cost)j+ 5tk is at a distance 13pi units along the curve from the point (0,-12,0) in the direction opposite to the direction of increasing arc length.

Thanks for any advice...

  • MATH--Please help!! -

    changing your equation to parametric form gave me
    x = 12sint
    y = -12cost
    z = 5t

    using the distance formula I got
    (12sint)^2 + (-12cost+12)^2 + (5t)^2 = (13pi)^2

    which simplified to the nasty transcendental equation

    25t^2 - 288cost - 1379.9631 = 0

    none of the online equation solvers I found were able to solve this equation, so I went to an old very user-unfriendly program based on Newton's Methos that I made up myself back in the 80's in "Dos-Basic" to find a solution near t = ±7.612121.
    (Perhaps you have a programmable calculator which gives you a better solution, nevertheless this one gave quite a significant error when I substituted.)

    I then used the positive result to get the point (11.651,-2.874,38.061)

    That point is 40.837 units away from your given point, and the value of 13pi is appr. 40.84, so .....

  • MATH--Please help!! -

    Thank you!

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Calc.

    sketch the curve using the parametric equation to plot the points. use an arrow to indicate the direction the curve is traced as t increases. Find the lenghth of the curve for o<t<1. Find an equation for the line tangent to the …
  2. calc

    for the parametric curve defined by x=3-2t^2 and y=5-2t ...sketch the curve using the parametric equation to plot of the point. use an arrow to indicate the direction of the curve for o<t<1. Find an equation for the line tangent …
  3. multivariable calc

    Please help! Find the point where the curve r(t) = (12sint)i -(12cost)j +5k is at a distance 13pi units along the curve from the point (0,-12,0) in the direction opposite to the direction of increasing arc length. (Hint: ty -13pi for …
  4. Maths

    1. Sketch the curves y=e^x and y=e^-2x, using the same axes. The line y=4 intersects the first curve at A and the second curve at B. Calculate the length AB to two decimal places. 2. Find the coordinates of the turning point on the …
  5. Math

    A curve is traced by a point P(x,y) which moves such that its distance from the point A(-1,1) is three times the distance from the point B(2,-1). Find the equation of the curve and identity.
  6. Math (repost, URGENT)

    A curve is traced by a point P(x,y) which moves such that its distance from the point A(-1,1) is three times the distance from the point B(2,-1). Find the equation of the curve and identity.
  7. 12th Grade Calculus

    1. a.) Find an equation for the line perpendicular to the tangent curve y=x^3 - 9x + 5 at the point (3,5) [* for a. the answer that I obtained was y-5 = -1/18 (x-3) ] b.) What is the smallest slope on the curve?
  8. Math

    Suppose you start at the point (0,0,3) and move five units along the curve x=3sint, y=4t, z=3cost in the position direction. Where are you now?
  9. calculus

    a particle is moving along the curve whose equation is" y=x^2?
  10. Maths

    A curve is such that dy/dx = 2- 8(3x+4)^-1/2 - A point P moves along the curve in such a way that the x-coordinates is increasing at a constant rate of 0.3 units per second. Find the rate of change of the y-coordinates as P crosses …

More Similar Questions