Plot two waves on excel: $\cos(f_1)$ and $\cos(f_2)$ and their sum $[\cos(f_1) + \cos(f_2)]$. The frequencies of the waves are $f_1= 2\pi*f$ and $f_2= 2 \pi*f*(1.1)$. Assume $f=1$
My question is how do we find the sum of 2 waves? and if there is a third wave $\cos(f_3)$ with $f_3= 2 \pi*f*(1.2)$. How do we find the sum of 3 waves?