Program using both conditional and loop

I don't know how to make continuos plot with different condition, i attach the formula and expected output. Thank you so much!

Answer 1

[Walter Roberson]

For example

for t = 0:.01:3
    if t < 0.2
        Y = t.^2 + 1;
    elseif t <= 1
        Y = (t - 1/4).^3 - t.^2 + sin(pi*t);
    else
        Y = cot(t .* pi);
    end
    Now record t
    Now record Y
end

plot(recorded_t, recorded_Y)

[Felvie Valerie Leong]

I can't run the 'Now record t' and 'Now record Y' code

[Walter Roberson]

function Now(flaff, varname)
   assert(strcmp(flaff, 'record'), 'Now what??')
   persistent recorded_t recorded_Y
   switch varname
       case 't'
           current_t = evalin('caller', 't');
           recorded_t(end+1) = current_t;
       case 'Y'
           current_Y = evalin('caller', 'Y');
           recorded_Y(end+1) = current_Y;
       otherwise
           error('Now can only record t or Y');
   end
end