Find the intervals on which f is increasing and the intervals on which it is decreasing f x cos x on Select the correct choice and if necessary fill in the answer box es within your choice A The function is increasing on the open interval s and decreasing on the open interval s Simplify your answers Type your answers in interval notation Type exact answers using as needed Use a comma to separate answers as need OB The function is increasing on the open interval s The function is never decreasing Simplify your answer Type your answer in interval notation Type exact answers using as needed Use a comma to separate answers as needed OC The function is decreasing on the open interval s The function is never increasing Simplify your answer Type your answer in interval notation Type exact answers using as needed Use a comma to separate answers as needed OD The function is never increasing or decreasing