I can not write piecewise function

I need to write piecewise function and plot it on matlab. But I couldn't do it. Here is my code. I need T_16 in terms of theta_12 with following conditions:

T_16 = 10*theta_12/0.17 if 0<=theta_12<=0.17

10 if 0.17<=theta_12<=3.5

215.88-10*theta_12/0.17 if 3.5<t=heta_12<=3.68

0 if 3.68<=theta_12<=2*pi()

clear; close all;

AB=140; A0_A=30; A0_B0=70; B0_Q=80; Q_C0=30;

sampling=3600;

theta_12=linspace(0,2*pi(),sampling+1);

theta_12=theta_12(1:end-1)';

theta_13=zeros(sampling,1);

s_43=zeros(sampling,1);

s_65=zeros(sampling,1);

theta_16=zeros(sampling,1);

for a=1:1:sampling

s_43(a)=(A0_A*A0_A*(1+2*(A0_B0/A0_A)*cos(theta_12(a)))+A0_B0*A0_B0)^0.5;

theta_13(a)=atan2(A0_A*sin(theta_12(a)),A0_B0+A0_A*cos(theta_12(a)));

theta_16(a)=atan2(-(AB-s_43(a))*sin(theta_13(a))-B0_Q,-(AB-s_43(a))...

*cos(theta_13(a))+Q_C0);

s_65(a)=(Q_C0*Q_C0+B0_Q*B0_Q+(AB-s_43(a))*(AB-s_43(a))-...

2*Q_C0*(AB-s_43(a))*cos(theta_13(a))+2*B0_Q*...

(AB-s_43(a))*sin(theta_13(a)))^0.5;

end

figure (1)

plot(theta_12*180/pi(),theta_13*180/pi(),...

theta_12*180/pi(),theta_16*180/pi());

legend("theta_{13}","theta_{14}");

xlabel("Angle theta_{12} (degree)");

ylabel("Angle (degree)");

title("Angles");

figure (2)

plot(theta_12*180/pi(),s_43,theta_12*180/pi(),s_65);

legend("s_{43}","s_{65}");

xlabel("Angle theta_{12} (degree)");

ylabel("Distance mm");

title("Angles");

syms theta_12

T_16 = piecewise((0<theta_12)&(theta_12<0.17),10*theta_12/0.17 ...

,(0.17<theta_12)&(theta_12<3.5),10 ...

,(3.5<theta_12)&(theta_12<3.68),(215.88-10*theta_12/0.17) ...

,(3.68<theta_12)&(theta_12<(2*pi())),0);

fplot(T_16)

Answer 1

[Voss]

sampling=3600;
theta_12=linspace(0,2*pi(),sampling+1);

T_16 = zeros(1,sampling+1);

% idx = theta_12 >= 0 & theta_12 <= 0.17;
% theta_12 is always >= 0 so you don't need to specify that condition
idx = theta_12 <= 0.17;
T_16(idx) = 10*theta_12(idx)/0.17;

idx = theta_12 >= 0.17 & theta_12 <= 3.5;
T_16(idx) = 10;

idx = theta_12 >= 3.5 & theta_12 <= 3.68;
T_16(idx) = 215.88-10*theta_12(idx)/0.17;

% % T_16 is initialized to zeros, so you don't need the last calculation
% idx = theta_12 >= 3.68 & theta_12 <= 2*pi;
% idx = theta_12 >= 3.68;
% T_16(idx) = 0;

figure();
plot(theta_12,T_16);

[Emirhan Artik]

Thank you sir.