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Asked by Ali on 4 Mar 2011

I know Parabola have formula z=x^2+y^2 now I want to plot it when it has simple shifted like image: http://i55.tinypic.com/33y50kx.gif I know how to plot3 or surf but I don't know how to plot3 this one.

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Answer by Paulo Silva on 4 Mar 2011

plot3(X+10,Y+10,Z); %this shifts the parabola 10 units on both x and y axis

Ali on 5 Mar 2011

Please check out this

http://www.mathhelpforum.com/math-help/f43/parabola-polar-coordinates-173404.html

I need this type of shifting!

Answer by Paulo Silva on 5 Mar 2011

x=-10:0.1:10; y=x; z=x.^2+y.^2; ang=pi/4; sm=[cos(ang) 0 sin(ang) 0 1 0 -sin(ang) 0 cos(ang)]; r=sm*[x;y;z]; x=r(1,:);y=r(2,:);z=r(3,:); [x,y]=meshgrid(x,y); plot3(x,y,z)

Ali on 5 Mar 2011

Rotation is better!

what you code is not what I want.

My code:

clc

clear all

spi=sin(pi/4);

cpi=cos(pi/4);

f=0:pi/20:pi;

t=0:(2*pi)/20:2*pi;

[F T]=meshgrid(f,t);

x=sin(F).*cos(T);

y=sin(F).*sin(T);

z=(x.^2+y.^2);

w=[cpi 0 -spi;0 1 0;spi 0 cpi];

surf(x,y,z);

This code just draw Parabola without rotation how can I do w*[x,y,z]??

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