How to color RED to the lower portion of the curve

How to color RED to the lower portion of the curve y=x^2

x = 1 : 0.1 : 10;
y = x.^2;
plot(x,y)
axis([1 10 0 100])

Answer 1

[Kye Taylor]

Replace the

plot(x,y)

command with

area(x,y,'FaceColor',[1 0 0])

[Atom]

Thanks for this reply. It works good. If I want to color the upper region, then what should be the code?

[Kye Taylor]

The command

patch(x,y,'b')

will add blue above the plot.

(How about showing a little love and accepting this answer.)

[Atom]

Thanks a lot. Your 1st code is great. The second code patch(x,y,'b') colors the upper portion but not the whole upper part. The curve y = x.^2; divides the x-y plane in two parts. I want to color the whole upper part. Please suggest me once more.

With best regards and cordial thanks, Pallav

[Kye Taylor]

Ohhh. i see what you mean. (I had my parabola symmetric about x = 0, and not just in the first quadrant). Try this

x = 1 : 0.1 : 10;
y = x.^2;
area(x,y,'FaceColor',[1,0,0])
patch([x,0],[y,100],'b')
axis([1 10 0 100])

[Atom]

Please suggest about the meaning of patch([x,0],[y,100],'b').

[Kye Taylor]

the first two inputs to patch can be thought of as points that define vertices of some polygon. the vectors x and y are the lower parts of that polygon. By adding a point (0,100) to the set of vertices, we get the top left corner of the polygon. Without that vertex, the behavior was as you said above, only the "upper portion" was colored instead of the "whole upper part".