Question

Please help me with this question

Answer 1

cosθ₁ = -
`(5)/(13)`

Explanation:

Given

sinθ₁ = -
`(12)/(13)` =
`(opposite)/(hypotenuse)`

This is a 5- 12- 13 right triangle

with opposite = 12, adjacent = 5 and hypotenuse = 13

Given θ₁ is in the 3rd quadrant where cosθ₁ < 0 , then

cosθ₁ = -
`(adjacent)/(hypotenuse)` = -
`(5)/(13)`