Hi, I am learning trigonometric graphs and transformations as I am learning my SHM equations and I have a doubt: Firstly, I have a hard time defining angular frequency and that might be one of the sources of my problem. Can anyone help me with that? Is it simply how many full, 2pi rotations it performs in one second? Now, let's take this equation: x = xo cos(ωt) ω = 2π / T or 2πf Firstly, the reason why we use 2π / T as omega: My teacher said it but I can't remember perfectly - this is how he said it more or less: 2π would be one complete cycle. Therefore when the t, representing time, in the equation equals the time period, T, we must have an answer of 2π as what we are applying the cosine function. So we have to find something, that when multiplied to t will equal to 2pi nt = 2π n = 2π / T Is that it? Something, n, multiplied by time must yield 2π? And 2π / T = ω Thanks, Peter G.