What should I do if I want to rotate a line?

For example, we have line : y = 2*x; I want to rotate the line by 30 degrees in a counterclockwise direction.

What should I do ? Any suggestions?

[Walter Roberson]

Rotate it around which point?

Answer 1

[Friedrich]

Hi,

In the case its rotating around the origin see here.

f = @(x) 2*x;

x = 0:0.1:10;
angl = 90;

rot_mat = @(angl) [cos(angl) -sin(angl); sin(angl) cos(angl)];
mat = rot_mat(deg2rad(angl));

f_rot = mat*[x;x*2];
plot(x,f(x),f_rot(1,:),f_rot(2,:));

legend('original','rotated')