How to make a piecewise function? (2025)

syms t

f1x = 2*cos(t);

f2x = cos(t);

f3x = 2*cos(t)+3;

f4x = cos(t)+4;

f5x = 2*cos(t)+5;

pwx = piecewise(0<=t & t<pi/2,f1x, pi<=t & t<3*pi/2,f2x, 3*pi/2<=t & t<2*pi,f3x, 0<=t & t<pi,f4x, pi<=t & t<3*pi/2, f5x);

fplot(pwx)

fig = figure();

ax = gca();

hold(ax);

grid on

daspect([1 1 1]);

a = 2;

b = 1;

fplot(@(t) a*cos(t), @(t) a*sin(t), [0, pi/2], 'Color', 'r', 'LineWidth', 1.5);

fplot(@(t) b*cos(t)+3, @(t) b*sin(t), [pi, 3*pi/2], 'Color', 'b', 'LineWidth', 1.5);

fplot(@(t) a*cos(t)+3, @(t) a*sin(t)+1, [3*pi/2, 2*pi], 'Color', 'g', 'LineWidth', 1.5);

fplot(@(t) b*cos(t)+4, @(t) b*sin(t)+1, [0, pi], 'Color', 'k', 'LineStyle', '--', 'LineWidth', 1.5);

fplot(@(t) a*cos(t)+5, @(t) a*sin(t)+1, [pi, 3*pi/2], 'Color', 'k', 'LineWidth', 1.5)

fplot(@(t) t, @(t) -1*ones(size(t)), [5 6], 'Color', 'm', 'LineWidth', 1.5)

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syms t

a = 2;

b = 1;

f1x = a*cos(t);

f2x = b*cos(t)+3;

f3x = a*cos(t)+3;

f4x = b*cos(t)+4;

f5x = a*cos(t)+5;

f1y = a*sin(t);

f2y = b*sin(t);

f3y = a*sin(t)+1;

f4y = b*sin(t)+1;

f5y = a*sin(t)+1;

f1z = @(t) 0;

f2z = @(t) 0;

f3z = @(t) 0;

f4z = @(t) t;

f5z = @(t) pi;

figure

hold on;

pwx = piecewise(0<t & t<pi/2,f1x, pi<t & t<3*pi/2,f2x, 3*pi/2<t & t<2*pi,f3x);

pwy = piecewise(0<t & t<pi/2,f1y, pi<t & t<3*pi/2,f2y, 3*pi/2<t & t<2*pi,f3y);

pwz = piecewise(0<=t & t<pi/2,f1z, pi<=t & t<3*pi/2,f2z, 3*pi/2<=t & t<2*pi,f3z);

fplot3(pwx, pwy, pwz, [0 2*pi])

pwx = piecewise(0<t & t<pi,f4x, pi<t & t<3*pi/2, f5x);

pwy = piecewise(0<t & t<pi,f4y, pi<t & t<3*pi/2, f5y);

pwz = piecewise(0<t & t<pi,f4z, pi<t & t<3*pi/2, f5z);

fplot3(pwx, pwy, pwz, [0 2*pi])