Angle of electron in an electric field

[Drizzy]

Homework Statement

https://imgur.com/zEoCpc0

I am trying to figure put the angle and my attempt is tanx=sy/sx (I have calculated a value for the distances)

But my book is saying: tanx =vy/vx

I don't understand why my way of solving it is wrong... I don't get the same answer for x :/

 

[TSny]

Suppose you drive your car around a corner from point A to point B. The direction you are traveling when you get to B is given by the direction of your velocity V_B at B. The angle θ, such that tanθ = s_y/s_x, is the angle of the red line that connects points A and B. But this is not the direction that you are traveling at B.

 

[cheapstrike]

You are calculating two different angles. Here tanθ_s≠tanθ_v. See this picture for clear explanation:

Original post link.