190k views
4 votes
2 homework questions:

2 homework questions:-example-1
User Dnaranjo
by
8.9k points

1 Answer

5 votes

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
by
8.5k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories