Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Equation of y vs x

  1. Nov 2, 2004 #1
    if:
    x=4.28t+0.181
    y=6.47t^2+4.51t+0.455

    what is equation of the graph of y vs x?

    I lost all my data for this physics project and all I have left are these notations. I would be able to find an equation if I had my graph. Any help would be appreciated.

    -UX
     
  2. jcsd
  3. Nov 2, 2004 #2

    Pyrrhus

    User Avatar
    Homework Helper

    those are parametric equations isolate t, then substitute in the other, and graph it.
     
  4. Nov 2, 2004 #3
    I didn't catch that, can you explain it in more detail?
     
  5. Nov 2, 2004 #4
    I think he means that find t in term of x and subsitute the t into the second equation of yours.
     
  6. Nov 2, 2004 #5

    Pyrrhus

    User Avatar
    Homework Helper

    sorry, i was away, yes what leong said.
     
  7. Nov 2, 2004 #6
    ahh...so it's similar to a system of equations
     
  8. Nov 3, 2004 #7
    Urban, the graph of the equations would be a parabola. I'm not real good at math but I think you can graph the equation by substituting values for t in both equations and evaluating to get the x and y points for each value of t. For instance, for t=0, x=0.181 and y=0.455 ... for t=1, x=4.461 and y=11.435 ... for t=2, x=8.741 and y=35.355 and so on for as many + and - values of t as you need. Plot the points and connect them as a smooth curve.
     
  9. Nov 3, 2004 #8

    HallsofIvy

    User Avatar
    Science Advisor

    Yes, but that's irrelevant to the question asked.
     
  10. Nov 6, 2004 #9
    Well, Ivy, I don't believe it is irrelevant. Urban did say the equation could be found with the graph and any help would be appreciated.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook