Isabella was asked to solve the following trigonometric equation for 0 < x < 2π.
sin(x) = cos(2x) = 0
-
Isabella worked the problem the following way:
Line 1: sin(x) (1 - 2 sin²(x)) =
-
Line 2: sin(x) - 1+2 sin²(x) = 0
Line 3: 2 sin² (x) + sin(x) = 1
Line 4: sin(x) (2 sin(x) + 1) = 1
Line 5: sin(x) = 1,
Line 6: sin(x) = 1,
Line 7: x = 0, π
2 sin(x) + 1 = 1
sin(x) = 0
A. Isabella made a mistake in her work. In what line did the mistake occur? Justify your answer. (6
points)
B. What are the correct answers? Leave answers as exact values. WORK DOES NOT NEED TO BE
SHOWN. (6 points)