Wave Equation
How are derivatives of y(x,t) with respect to both x and t related => wave equation
length of segment is ?x and its mass is m=? ?x
net force in vertical direction is Fsin?2 - Fsin ?1
but sin?~ ?~tan ? when ? is small
net vertical force on segment is F(tan?2 - tan ?1 )
but slope S of string is S=tan ? = ?y/?x
net force is F(S2 - S1) = F ?S = ma = ??x?2y/?t2