Answers to select problems from yesterdays Homework

37) 4pi/5

41) It is not defined by the range so we cannot use the formula directly as in problem 37. However, we can find a reference angle in the interval (-pi/2, pi/2). The angle of sin(9pi/8) is in quadrant III so it is negative. The reference angle of 9pi/8 is pi/8. Since pi/8 is in the interval of -pi/2 to pi/2. We can apply the equation to get the answer. Remember that sin is negative. So the answer is -pi/8.