In quadrant II, where the cosine function is negative, the reference angle (θ') is π - θ. If tan(θ) = -√19, the reference angle is found by taking the inverse tangent of √19 and subtracting it from π. The cosine of the reference angle gives cos(θ').
In quadrant II, the cosine function of an angle is negative. To find the value of cos(θ), we need to find the reference angle (θ').
In quadrant II, the cosine function of an angle is negative. So, to find the value of cos(θ), we need to find the reference angle (θ'). The reference angle is the acute angle formed between the x-axis and the terminal side of the angle in the unit circle.
In quadrant II, the reference angle is π - θ. Therefore, cos(θ) = -cos(θ').
Since tan(θ) = -√19, we can find the reference angle by taking the inverse tangent of √19 and then subtracting it from π. Then we can find cos(θ') by taking the cosine of the reference angle.