A drum is a musical percussion instrument, consisting of a membrane which is usually stretched taut over a cylindrical tube that is open at the other end. The membrane is struck, either with the hand or some other object, and the tube forms a resonating chamber for the resulting sound. A drummer is a person who plays the drums.
... divide by it.)
The symbol
<math>\pm \sqrt {b^2-4ac}</math>
in the formula should be understood as "either of those element(s) of the field whose squar ...