The motion of a particle is given by x = A sin ωt + B cos ωt. The motion of the particle is
As x given in the question satisfies the simple harmonic motion equation
∴ the above equation in question is a simple harmonic motion.
And can be represented as
Where 
, δ is the phase difference 
and 
.
And 
,
In which 
can also be represented as
,
∴ δ can be written as 
And 
becomes 
Hence, amplitude becomes
.
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