**1. The problem statement, all variables and given/known data**

prove that

**2. Relevant equations**

-1 [tex]\leq[/tex] sin t [tex]\leq[/tex] 1

**3. The attempt at a solution**

the area under the graph is increasing as x increases

also, i tried to write it the sigma way:

i got stuck trying to figure out how to work with sine in sigma notation, but i'm not even sure if my attempt would get anywhere

can anyone give me any pointers on how to do this?