What is the local maximum of f(x) = cos(t) + cos(t+pi/2)? For max we would take the first derivative, set it to zero and solve. But how do you solve f'(x) = -sin(t) - sin(t+pi/2) = 0 Also, this is ...

Figure 4. A snapshot, in time, of two complex numbers whose exponents, and thus their phase angles, change with time. The notion of negative frequency is often troubling to engineers who've spent so ...