In the following problem, the range of the periodic function f(x) is [a, b]. Find b-a. f(x)=

I know the derivative, I just don't know what to do from there.

f'(x)= = cos(2x)

Disclaimer: This is for AP Calculus AB

The earth's inner core is the earth's innermost part. it is primarily a solid ball with a radius of about 1,220 km (760 miles), which is about 70% of the moon's radius.[1][2] it is composed of an iron–nickel alloy and some light elements. the temperature at the inner core's surface is approximately 5,700 k (5,430 °c), which is about the temperature at the surface of the sun. 

Psychologists often talk of the magical number "7" - so it is generally assumed that we can keep 7 (more or less, so 5-9 is the correct answer) items in our short term memory - we know this as a result of many experiments.

we can increase this by chunking, so for example "7 8 9 5 3" is harder to remember than "78 95 3" - try it yourself!

the answer is a)