9514 1404 393
Answer:
(d) ±√15/4
Step-by-step explanation:
Useful trig identities are ...
cos(x) = 1/sec(x)
sin(x) = ±√(1 -cos²(x))
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Using these, we see that ...
sin(θ) = ±√(1 -(1/sec²(θ))) = ±√(sec²(θ) -1)/sec(θ)
sin(θ) = ±√(4² -1)/4 = ±√15/4
