Question

Use a graphing utility to solve the equation on the interval 0degrees less than or equal to x less than 360 degrees. Cos^2x+cosx -1 =0

Answer 1

notice is a quadratic, the "solution" will be where y = 0, as you can see "y" is indeed equals 0, \(\bf Cos^2x+cosx -1 =y\implies Cos^2x+cosx -1 =0 \qquad \qquad y = 0\)

when y = 0, is where the graph TOUCHES the x-axis, whatever "x" is at those points, is the "solutions"