Task:
Replace in ${y(x)=\frac{V_\text p\cdot e}{2\cdot \text d\cdot m \cdot {v_0}^2}\cdot x^2}$ the initial speed ${v_0}$ of the electrons caused by the electron gun with a term that only depends on the acceleration voltage $V_{\text{a}}$, which can be modified in the experiment.

Hint 1:

Replace ${v_0}^2$ with the help of the red framed term, which depends only on $V_{\text{a}}$ and some constants.

Hint 2:

${v_0}^2$ must be replaced, so the red framed term must be squared. So the root disappears.

Useable variables:

x = position on x-axis
Va = acceleration voltage
Vp = capacitor voltage
e = charge of an electron
m = mass of an electron
d = distance between capcitor plates

typing tips:

x² must be typed as x*x
2x must be typed as 2*x

Please note the following :

Useable variables:

x = position on x-axis
v0 = velocity in x-direction
ay = accelertation in y-direction
Va = acceleration voltage
Vp = capacitor voltage
e = charge of an electron
m = mass of an electron
d = distance between capcitor plates