Practice problem5





                     In this page practice problem5 we are going to solve and practice quadratic equations with complex roots.

                    . While solving a quadratic equation we will get either real or imaginary roots. So before start solving the equations, let us find the value of the discriminant which tells us about the nature of the roots.

Solutions:

       1. x²/2=2x-4

       Here the left hand side of the equation is in fraction form. To remove the denominator we have to multiply the whole equation by 2.

          2(x²/2)  =  2(2x-4)

             x²      =   4x -8

        Now let us write all terms of the equation in one side.

            x²-4x+8 =0

        Here a= 1, b= -4 and c=8

         The value of the discriminant is √(-16), which is negative. So we will get complex roots. Now let us solve for x.

                                    =   (4±4i)/2

                                    =    2±2i

 The roots are                 =    2+2i,  2-2i



Now let us solve the next equation.   

           x²-x+3=0

      Here a= 1, b= -1 and c=3

Here the value of the discriminant is √(-11), which is negative. So we will get complex roots. Now let us solve for x.

The roots are                 =  (1+i√11)/2, (1-i√11)/2 



Now let us do the next problem.

          2x²-2x+5=0

      Here a= 2, b= -2 and c=5


Here the value of the discriminant is √(-36), which is negative. So we will get complex roots. Now let us solve for x.

The roots are                 =    (1+3i)/2,  (1-3i)/2

Problems for practice:

  1. x²-3x+1=0
  2. 2x²-x+4=0

Teachers and parents can guide the student to practice the problems given in practice problem5 and get a good knowledge about the complex numbers. Two problems are given for practice. students can solve them using the method discussed above. If you have any doubt in any problem, you can contact us, we will clear all your doubts.





[?]Subscribe To This Site
  • XML RSS
  • follow us in feedly
  • Add to My Yahoo!
  • Add to My MSN
  • Subscribe with Bloglines