Look at the picture.
Definitions:
We have:
and Quadrant II (x < 0, y > 0)
Therefore x=-3 and y = 2. Calculate r:
Substitute to the formula of cosine:
Answer: a.
Which product is positive?
1 answer:
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Check the picture below.
notice that the point A is the center of the circle, and thus the ∡BAF is a central angle, and the arc BF gets its angle measurement from ∡BAF, in red.
now, notice, ∡BAF has a twin vertical angle, namely ∡CAE in green, and the arc made by ∡CAE is congruent to BF.
notice that the point A is the center of the circle, and thus the ∡BAF is a central angle, and the arc BF gets its angle measurement from ∡BAF, in red.
now, notice, ∡BAF has a twin vertical angle, namely ∡CAE in green, and the arc made by ∡CAE is congruent to BF.