A string on a musical instrument is 20cm long and is fastened at both ends. The total mass of the string is .02 kilograms. We desire to cause the string to vibrate at a fundamental tone of 500Hz when it is plucked or bowed. To what tension should the string be tightened? Using the same instrument, write the equations for the two traveling waves on the string, specifying as completely as possible (i.e., numerically) all function arguments.