Given a curve like this with a slider for x:
Manipulate[
f[x_] := .5*2 x^2;
Plot[{f[x]}, {x, 0, 1}],
{{x, .5, "X"}, 0, 1, .01}
]
How can I draw a horizontal arrow from the curve at the current value of x to the y axis with the y value text on the arrow.
Thank you. Joe Rimback
