Question

Solve the given equation over the interval [0, 2.2): 2 cos2 x + cos x + 15 = 0.X = 0 and x = 2.0T57x= - and x=66There are no real valued solutions for the equation.T371x= and x =2

Answer 1

The given function is

`2\cos ^2x+\cos x+15=0`

Solve the equation to get:

`\cos x=\frac{-1\pm\sqrt[]{1-4\ast2\ast15}}{4}=\frac{-1\pm\sqrt[]{-119}}{4}`

The square root of a negative number is not real hence there are no real valued solutions

Option C is correct.