What is the phase constant in SHM?

[polymerase]

The graph shows the position x of an oscillating object as a function of time t. The equation of the graph is x(t)=Acos(wt + \phi)
where A is the amplitude, w is the angular frequency, and \phi is a phase constant. The quantities M,N, and T are measurements to be used in your answers.

See attached image.

What is \phi in the equation?

 

[polymerase]

can anyone help me?

 

[Astronuc]

The attachment has to be approved, but the phase angle (constant) is found for example when t = 0, and knowing x(t=0) = A cos \phi, or

\phi = cos^-1 (x(0)/A), or

if x(t) is known at t, then

\phi = cos^-1 (x(t)/A) - wt

 

[kawsarmirdha]

the answer leads to 0.5pi.