Question

Given that sine = 0.87, using sin²0 + cos²0 = 1,

find cose (in Quadrant I). Show all your work for
credit - answer given to three decimal
approximation.

Answer 1

Answer: 0.493

Work Shown:

`\sin^2(\theta)+\cos^2(\theta)=1\\\\\cos^2(\theta) = 1-\sin^2(\theta)\\\\\cos(\theta) = √(1-\sin^2(\theta)) \ \ \ \text{.... cosine is positive in Q1}\\\\\cos(\theta) = √(1-(0.87)^2)\\\\\cos(\theta) \approx 0.4930517\\\\\cos(\theta) \approx 0.493\\\\`