I want to scetch the function E below.
The original function (potential) is V below, $V_0$ is constant, then a gradient was found for the field $E = - \nabla V$
$$V(x,y,z)=4.00|x|+V_0$$
$$E = 4a_x \text{ for } \ x <0 \\ E = -4a_x \text{ for } x >0$$
Like, this function seems to be in 4D and not 3D and how can I scetch it? If this were 3D then 4 is the value of z for all values x<0, right? Then -4 is value for all z that are x>0. But then one more thing that complicates it is that it is a vector function. So should I just bascially draw arrows in which direction the vector function is increasing?
Well E only depends on the x component. So it is without loss to restrict your drawing of E to an x number line. You can then draw arrows to indicate the direction of E at every point x, and bolden the vector darker to indicate a greater relative magnitude of E (if the magnitude is constant, then this is not an issue).
Also, if you have to graph V, it is without loss to do so in two dimensions in a V-x plane, since V is independent of y,z.