Remember how the tangent function is defined as
Now where exactly are the vertical assymptotes? Well, where cosx = 0, because anything over 0 is undefined, and where a value is undefined, you are required to draw a vertical assymptote.
Now where exactly are the x interecepts? Well, where sinx = 0, because remember, an x-intercept is where y = 0, or where it crosses the x-axis, meaning where the tangent function is equal to 0.
So the x-intercepts are at where sinx = 0.