SOLUTION: Find sin(2x), cos(2x), and tan(2x) from the given information. sec(x) = 4, x in Quadrant IV

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Question 1171343: Find sin(2x), cos(2x), and tan(2x) from the given information.
sec(x) = 4, x in Quadrant IV
Answer by Solver92311(821) About Me  (Show Source):
You can put this solution on YOUR website!

QIV → cos, sec > 0; sin, csc, and tan < 0

cosine is the reciprocal of secant, so if then .

Then since , but since sine is negative in QIV,



Then since tangent is the quotient of sine over cosine and cosecant is the reciprocal of sine, we have:



and



Then





and


The rest is just arithmetic -- that's on you.

John

My calculator said it, I believe it, that settles it

From
I > Ø