Trigonometry problem, please help?

2016-03-01 7:10 am

Problem: sec ø=5/3. find sin(ø)

回答 (3)

2016-03-01 8:36 am

Right angled triangle with sides 3 , 4 , 5
cos ø = 3/5
sin ø = 4/5

👍 1 👎 0

2016-03-01 7:22 am

secϕ = 5/3

1/cosϕ = 5/3

cosϕ = 3/5

1- cos²ϕ = 1 - (3/5)²

sin²ϕ = 16/25

sinϕ = √(16/25) or sinϕ = -√(16/25)

sinϕ = 4/5 or sinϕ = -4/5

👍 1 👎 0

2016-03-01 10:49 am

sec(ø)=5/3 so
cos(ø)=3/5.
Since sin^2ø=1-cos^2ø = 1-9/25=16/25,
then sin(ø) =-4/5 or +4/5

👍 0 👎 0