Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have this equation:

v*t-(u*g*t^2)/2 = d

And I'm having trouble solving it for t. Mathematica gave me two results,

t -> (v+-Sqrt[-2 d g u+v^2])/(g u)

Have no idea how it got it. I did manage to get to t = (d+0.5u*g*t)/v or t^2 = (v*t-d)/(0.5u*)

Any help will be appreciated. Thanks!n

share|cite|improve this question
up vote 4 down vote accepted

The equation can be written as $-ugt^2+2vt-2d=0$. The quadratic formula then gives $t=\dfrac{-2v\pm\sqrt{4v^2-4(-ug)(-2d)}}{-2ug}$, which is equivalent to what Mathematica gave you.

share|cite|improve this answer
Thanks! Helped me a lot. – Mark Segal Jan 24 '12 at 13:51

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.