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Problem
Ryker tried to solve the following equation, where

is in radians to the nearest hundredth, in the interval from

to

, but he made a mistake.

Here is Ryker's work.






Of the solutions, only

is in the interval from

to

, so

.
What was Ryker's mistake?
Choose 1 answer:
Choose 1 answer:
(Choice A) Ryker evaluated

in degrees instead of in radians.
A
Ryker evaluated

in degrees instead of in radians.
(Choice B) Ryker used an identity that only applies to the sine function, not to the cosine function.
B
Ryker used an identity that only applies to the sine function, not to the cosine function.
(Choice C) Ryker forgot to use negative

-values which would reveal more solutions in the interval.
C
Ryker forgot to use negative

-values which would reveal more solutions in the interval.
(Choice D) Ryker gave solutions that were outside of the interval.
D
Ryker gave solutions that were outside of the interval.