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Having trouble solving this one. Class is dynamics. 2D, constant accel.

Shooting a cannon at a point above the initial. Inital velocity is 400m/s

Cannon is at point A (origin) and we're shooting at point B @ (5000m, 1500m)

I'm asked to find the two thetas that satisfy.

So i got this so far, basicly the givens.

In the x:

ax = 0

vx = v0*cos(Θ)

x = v0*cos(Θ)*t

In the y:

ay = -g

vy = v0*sin(Θ)-gt

y = v0*sin(Θ)*t-(1/2)gt2

I tried to eliminate t is the y position equation by

1) solving x for t

2) subing into y(Θ,t) for t to get y(Θ)

3) solving for Θ

I cant get through solving for Θ. Can I use the quadradic equation on y(Θ) to solve for Θ? How do i do that?

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# Dynamics: solve both trajectories

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