+118608 The wavelength here is \(\pi \) and that is the only transformation from the parent function of y=cos x
If y= cos nx then the wavelength will be \(\frac{2\pi}{n}\)
so
\(\frac{2\pi}{n}=\pi\\ \frac{2}{n}=1\\ n=2\)
So it must be \(y=cos(2x)\)
Check by using Desmos graphing calculator.
Desmos is another tool that is very easy to use and very helpful to you.
