Given equation is x 2 +x+ 1 2 =0 .
Any equation of the form a x 2 +bx+c=0 has the solution
x= −b± D 2a
Here, D= b 2 −4ac is called the discriminant of the quadratic equation.
Therefore,
x= −1± 1−4×1× 1 2 2×1 = −1± 1−2 2 2
Square-root of 1−2 2
Comparing it with a 2 +2ab+ b 2 , we get
a 2 + b 2 =1 (1)
And
2ab=−2 2 (2)
Further solving these equations, we get
a=1,b=− 2 i
Thus, x= −1±( 1− 2 )i 2 .