in a graph, "y" axis is the vertical axis and the blue curve is your function "f(x)". So, on the blue curve, trace and mark the place that is the highest in the given window. Notice that when "x" axis (the horizontal one) is π, the blue curve reaches its highest point,
For h(x)=2cos(x)+1, remember that the maximum value for cos(x) is "1". So, the maximum value forh(x)=2(1)+1=3
