The pressure P (in lbs per square foot), in a pipe varies over time. Four times an hour, the pressure oscillates from a low of 50 to a high of 260 and then back to a low of 50 . The pressure at time t=0 is 50 . Let the function f(t)=P denote the pressure in pipe at time tminutes.

Find a possible formula for the function P=f(t) described above.

period: ?

amp: 105

midline: y=155

y=105cosx+155

this is as far as i got i do not know what the period is