Given,
The displacement of an elastic wave is given by the function
y=3sinω t+4cosω t=y1+y2
Where y1=a1sinω t=3sinω ty2=a2cosω t=4cosω t
=4sin(ω t+π2)
where y is in cm
Phase difference, Δϕ=π2
Resultant amplitude of given wave
a=√a21+a22+2a1a2cosΔϕ
=√a21+a22
a=√32+42=5 cm
Final Answer: 5 cm