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2 homework questions:

2 homework questions:-example-1
User Dnaranjo
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1 Answer

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Explanation:

See image

tan x = 4/5 and cos x less than zero means sin x is less than zero too because tan x = sinx / cosx <=== ( in Q III)

sin / cos = 4/5

cross multiply to get

5 sin = 4 cos square both sides

25 sin^2 = 16 cos^2 remember: sin^2 + cos^2 =1 then cos^2 = 1 -sin^2 :

25 sin^2 = 16 (1-sin^2)

41 sin^2 = 16

sin^2 = 16 / 41 now square root both sides

sin = ± 4 / sqrt(41)

BUT remember...sin x is negative for this QIII angle: sin x = - 4/sqrt(41)

or sin x = - 4 sqrt (41) / 41

2 homework questions:-example-1
User Ravbaker
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