I have two questions regarding Standing Waves. [i.] Suppose two speakers face each other with 'x' distance between them. They have = frequency. If i were told to find the points of minimum or maximum interference (or sound pressure amplitude) between the speakers, what excactly am i calculating for? I understand that we could solve for wavelength (since we have the average speed of sound and frequency). Then, since we also have a distance for the sound wave to travel, we could find the number of wavelengths in that distance. But what now? I rejected my initial idea that the points of minimums are the nodes. So where are they? [ii.] Two wave equations are available, differing only in direction. They both have 'y', 'x' and 't' variables. To find the "maximum position of an element in the medium" at e.g. x=1cm, i believe i would calculate for y when x = 1cm. But what should 't' equal? EQuating t to 0 produces the correct answer, but why?? Thank you.