Quickly create symmetric/ antisymmetric piecewise function to use in simulink

I need to create the curve in red below.

It is a periodic piecewise function with period T = 2*pi, defined in the first quarter period [0,pi/2] by:

2M*1.73/pi* cos(x-pi/6)         if 0<x<pi/3
2M*1.73/pi* 1.73 * cos(x)      if pi/3<x<pi/2

where M = 0.907.

After that, as you can see in the picture, highlighted in red, the function continues between pi/2 and pi being the antisymmetric of the previous.

Between pi and 2*pi, again it is the symmetric of all the previous.

I am using this code

syms y(x);
M = 0.907;

coeff = 2 * M * sqrt(3)/pi;
cond1 = x>0&x<pi/3;
cond2 = x>pi/3&x<pi/2;
val1 =   coeff*cos(x-pi/6);
val2 =   coeff*sqrt(3) * cos(x);
y(x) = piecewise( cond1, val1, cond2, val2 );
fplot(y(x))

to plot the first quarter of the function.

I am able to wrap my mind and plot the function all the way up til 2*pi, but it is not flexible.

How can I quickly plot all the function in [ 0, 2*pi ]?

how can I make it periodic of period T = 2*pi?

Please keep in mind I don't want to discretize the function using any linspace, I should be able to query the function and get the exact value, not an interpolated one.

This is not school homework, the function comes from a book about three phase electric motor space vector modulation.

I plan of using this function as an output in simulink.

Thank you!