The tension in a string is $16\mathrm{.}0$ N $,$ and its linear density is $0\mathrm{.}829k\frac{g}{m}.$ A wave on the string travels toward the $-$x direction; it has an amplitude of $4\mathrm{.}97$ cm and a frequency of $15\mathrm{.}6$ Hz $.$ What are the $($a$)$ speed and $($b$)$ wavelength $($in terms of $m)$ of the wave? $($c$)$ Write down a mathematical expression $($like Equation $16\mathrm{.}3$ or $16\mathrm{.}4)$ for the wave, substituting numbers for the variables $A,f,$ and $.$