The number of visitors P to a website in a given week over a 1-year period is given by P(t)=118+ (1-89) 0.021, where t is the week and 1 st≤52 a) Over what interval of time during the 1-year period is the number of visitors decreasing? b) Over what interval of time during the 1-year period is the number of visitors increasing? c) Find the critical point, and interpret its meaning. a) The number of visitors is decreasing over the interval (Simplify your answer. Type integers or decimals rounded to three decimal places as needed. Type your answer in interval notation.)