A Cepheid variable star is a star whose brightness alternately increases and decreases. Suppose that Cephei Joe is a star for which the interval between times of maximum brightness is 5.4 days. Its average brightness is 4.0 and the brightness changes by +/-0.35. Using this data, we can construct a mathematical model for the brightness of Cephei Joe at time t, where t is measured in days:
B(t)=4.0+0.35sin(2pi(t)/5.4) a) find the rate of change after t days b)find the rate of increase after 1 day --- i found the derivative to be correct: 0.7pi/5.4cos(2pi/5.4)

Question

A Cepheid variable star is a star whose brightness alternately increases and decreases. Suppose that Cephei Joe is a star for which the interval between times of maximum brightness is 5.4 days. Its average brightness is 4.0 and the brightness changes by +/-0.35. Using this data, we can construct a mathematical model for the brightness of Cephei Joe at time t, where t is measured in days:
B(t)=4.0+0.35sin(2pi(t)/5.4) a) find the rate of change after t days b)find the rate of increase after 1 day --- i found the derivative to be correct: 0.7pi/5.4cos(2pi/5.4)

anonymous · Answer

when i plug in 1, to solve for t, im ending up with 0.41, while the answer in my textbook is 0.16; but we have the same derivative function, and we're just plugging in a 1?

anonymous · Answer

help!