# Problem with trigonometry

1. Oct 14, 2009

### henryc09

1. The problem statement, all variables and given/known data
In a certain collision problem the kinematics are determined by the following three equations:

u=u1cos(@) + SQRT(2) * u2
u1sin(@)=SQRT(2) * u2
0.5mu^2=0.5mu1^2 + 0.5(2m)u2^2

Use the first two equations to express u1 and u2 in terms of u, sin(@) and cos(@). Then substitute in the third equation and obtain solutions for sin(@).

2. Relevant equations
see above

3. The attempt at a solution
I have that u1=u/(sin(@)+cos(@) and u2=u/(SQRT(2)((cos(@)/sin(@))+1) and substitute those in to the third equation eliminating U and m, but having tried various methods cannot solve the trigonmetry equation. Any help would be greatly appreciated.

Last edited: Oct 15, 2009
2. Oct 14, 2009

### kuruman

This equation is confusing. I can divide both side by u2 and get sin(@)=SQRT(2) which can't be true.

3. Oct 15, 2009

### henryc09

Oops sorry, it should be u1sin(@)=SQRT(2)u2

4. Oct 15, 2009

### kuruman

OK. Now tell me what the unknown quantities are and what the known quantities are. In other words, we are solving for what in terms of what?