How did you get 1.9033,

solutions to the above equation is :

x1 = -1 + 2.5356i

x2 = -1 + 2.5356 i

In other words these give you no solutions,

Try to solve this quadratic equation:

x^2+2x+(9-7pi/2)=0 // cos((7 * pi) / 2) = 0

and remember that for the quadratic equation to give you real values:

(2n+1)pi/2 > 9 // solve for what values of n you get real values....