# Formula values and transposition

• Nov 30th 2012, 12:24 AM
maths2454
Formula values and transposition
Hi,

I have just sumitted a maths paper and one question has given me sleepless nights and I'm after advice:

The question:

Show that x = v1 + 1/2 at2

if v2 = v1 + at and x = (v1 + v2) t
-----------
2

I hadn't got a clue where to even start and made a complete hash of it!

Any advice where I should of started or what I should of done would be great.

Thanks :)
• Nov 30th 2012, 02:42 AM
BobP
Re: Formula values and transposition
These are, almost, the equations of motion of a body moving with a constant acceleration.

The first equation is wrong, it should be $\displaystyle x=v_{1}t+\frac{1}{2}at^{2}.$

Multiply the third equation by 2, and solve for $\displaystyle v_{2}t$; multiply the second equation by $\displaystyle t$ and substitute the $\displaystyle v_{2}t$.
• Nov 30th 2012, 04:10 AM
maths2454
Re: Formula values and transposition
Thanks.... but the 1 over 2 bit I am a little confussed over.... does it mean the square root of a?

It's been way to long since I have done this my brian is a little rusty!
• Nov 30th 2012, 04:41 AM
BobP
Re: Formula values and transposition
Your brian might well be rusty but I think you should be more worried about your brain.

$\displaystyle \frac{1}{2}at^{2}$ means $\displaystyle at^{2}$ multiplied by a half.
• Nov 30th 2012, 05:10 AM
maths2454
Re: Formula values and transposition
Thanks again..... I did a half of at^[2] which has given me the same answer luckily!