Matlab HIgh frequency sine wave generation

1. How do you add two sine waves with different frequencies in MATLAB?
2. How do you write a sine function in MATLAB?

How do you add two sine waves with different frequencies in MATLAB?

t = r + y; subplot(3,1,3); %plot (x,y);

How do you write a sine function in MATLAB?

Y = sin( X ) returns the sine of the elements of X . The sin function operates element-wise on arrays. The function accepts both real and complex inputs.