Homework Help Forum: Calculus (trig stuff)

Posted by Calculus (trig stuff) on Sunday, October 25, 2009 at 9:33pm.

How do I do these type of problems find the exact value. Do not use a calculator cos 7pi

• Calculus (trig stuff) - michael, Monday, October 26, 2009 at 12:24am

  2&pi is one full rotation around the circle, so you can think of 2&pi as being the same as 0. so 7 pi is the same as going around the circle 3 full times with 1&pi left over, to figure this out exactly you can do the following: (7/2) = 3 +1/2 the 3 is how many times we went 2&pi around the circle, and what we have left is (1/2)*2&pi or 1&pi cos(&pi) = -1 To do another example sin((9/2)&pi) well (9/2)/2 is the same as (9/2)*(1/2)=(9/4) we get 2 + 1/4 so we get 2 full rotations plus 1/4 of a full rotation. A full rotation is just 2&pi so: 2&pi*(1/4) = &pi/2 sin(&pi/2) = 1

  
  

Answer this Question

First Name:
School Subject:
Answer:

For Further Reading