Help with this question, please!! I need some help ASAP!
1 answer:
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7π/12 lies in the second quadrant, so we expect cos(7π/12) to be negative.
Recall that
which tells us
Now,
and so
We could do it by first writing
so that
and since , we have
# # #
Alternatively, we can just compute the product and take it mod 4:
and so we get the same result of 1.