Awave on a string is described by
d(x, t)=(3.6cm)× sin[2π(x/(4.8m)+t/(0.14s)+1)], where x is in m and t is in s.

what is wave speed, frequency and wave number?

also:
at t=0.42s, what is the displacement of the string at x=5.2m

!

We are given an equation which describes a wave on a string:

D(x,t) = 3.6cm * sin[2π (x/4.8m) + t/(0.14s) + 1)] 

where x is in meters
t is in seconds

at t = 0.42 seconds, and x = 5.2 m

First, convert the term into the equation with cm units:

D(x,t) = 3.6cm/100cm/m * sin[2π (x/4.8m) + t/(0.14s) + 1)] 

then, substitute the values of x and t

D(x,t) = 3.6cm/100cm/m * sin[2π (5.2/4.8m) + 0.42/(0.14s) + 1)] 

Solve for D, this is your displacement at x = 5.2 and at 0.42 seconds