I know the answer is 5pi/6.
I just have no idea how to get that answer!
I understand coterminals when starting with a degree...add or subtract 360 to get between 0 and 360. That makes sense to me. But how do i find it when starting with a radian? Please Explain!!
2pi to the square root of C???? What is C??? havent seen that yet...
Ok so I think I kind of understand how to subtract 2pi and come out with 5pi/6. But then how do I know thats between 0 and 2pi?? How do I know just from looking at it that the original problem, 17pi/6, isn't already between 0 and pi?
I feel like I have totally missed something here...I swear my book does not explain this lol.
how do we know which multiple of 2π to add/subtract?
0 ≤ 17π/6 + 2πk < 2π
multiply by 6:
0 ≤ 17π + 12πk < 12π
0 ≤ (17 + 12k)π < 12π
multiply by 1/π:
0 ≤ 12k + 17 < 12
-17 ≤ 12k < -5
multiply by 1/12:
-17/12 ≤ k < -5/12
since k is an integer between -5/12 and -17/12, it must be that k = -1.
therefore the angle we want is:
17π/6 - 2π = 17π/6 - 12π/6 = 5π/6