Final answer:
The value of cos θ given that (-5, 4) is a point on the terminal side of θ is -5/sqrt(41), which is approximately -0.7808.
Step-by-step explanation:
The value of cos θ can be found by using the x-coordinate of the point on the terminal side of θ. In this case, the given point is (-5, 4).
Since the x-coordinate is -5, we can calculate the value of cos θ by dividing -5 by the distance from the origin to the point, which is the magnitude of the vector represented by the point.
The magnitude of the vector can be found using the Pythagorean theorem, which gives us sqrt((-5)2 + 42) = sqrt(25 + 16) = sqrt(41).
Therefore, the value of cos θ is -5/sqrt(41), which is approximately -0.7808.