this makes no sense.
help please?
If cos Θ = -2/5 and tan Θ 0, what is the value of sin Θ?

Question

this makes no sense.
help please?
If cos Θ = -2/5 and tan Θ > 0, what is the value of sin Θ?

anonymous · Answer

$$\sin (\theta )=\sin \left(\cos ^{-1}\left(-\frac{2}{5}\right)\right) $$

anonymous · Answer

$$\sin (\theta )=\frac{\sqrt{21}}{5} $$

mallorysipp234 · Answer

i got a syntax error on my calculator. im still confused @robtobey

anonymous · Answer

if cosine is negative, which quadrant do you think theta is in?

mallorysipp234 · Answer

negative square root 21

negative square root 21 / 5

square root 21 / 5

square root 21 / 2

@sourwing @robtobey

anonymous · Answer

yes, which quadrant theta is in if cosine is negative?

anonymous · Answer

sin x = -(V21)/5 since tan x > 0. See drawing.

mallorysipp234 · Answer

It isn't square root 21/5

mallorysipp234 · Answer

@thu1935 so it's negative square root 21 / 5?

anonymous · Answer

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