Final answer:
The wavelength of the given wave equation is 2π/3.
Step-by-step explanation:
The given equation for the transverse displacement of the stretched string is y = 0.13 cos(3x - 27t). In this equation, the coefficient of x represents the wave number (k) and the coefficient of t represents the angular frequency (ω). The wavelength (λ) of the wave can be calculated using the formula λ = 2π/k.
For the given equation, k = 3, so the wavelength is λ = 2π/3.