I really need help with this calculus 1 question?

a) The rate of change brightness after 't' years

b) The rate of increase after five years

Step-by-step explanation:

a) Given B(t) = 5.0+0.55sin(   .....(1)

The rate of change of the brightness after 't' days that is

now differentiating equation (1) with respective to 't'

      { using d/dx(sin x) =cos x}

b) The rate of increase after five days    

substitute t = 5 in equation dB/d t

after calculation

step-by-step explanation:

once you graph it hit 2nd (the blue button) and graph

that takes you to a table of coordinates

on the left is x coordinates and on the right is y coordinates and an empty box

(you may have to scroll up/down in order to get ( x, 0)

29.5977692753

step-by-step explanation: