Given f(x)=a(x-h)^2+k, what is the effect of the following on the graph of the function?

Question

i) size of a
ii) sign of a
iii) value of h

Answer 1

increase |a| to expand the graph
change sign of a to flip it about the x axis
increase h to move it to the right

Answer 2

This is the equation of a parabola with axis of symmetry parallel to the y-axis. The vertex is located at (h,k).

If a is negative, the parabola is concave downward ( has a maximum) and if a positive the parabola is concave upward
(has a minimum).

If a inceases the parabola becomes narrower and vice versa.

The value of h moves the entire graph of the parabola up or down as k becomes larger or smaler.