Monday, May 25, 2015

Equation

Definition: An equation is a relation between two algebraic expressions symbolized by the sign of equality (=).
For example the equation 
     3x + 5 = 2x + 7
is true only for x = 2 and not foe x = 3.



Question: Write the nature of roots of quadratic equation   
Solution: Since the roots of the quadratic equation    

              ax^2+bx+c=0

are given by    
               x=\frac{-b\pm\sqrt{b^2-4ac\ }}{2a}.

The nature of roots shall depend on the   b2 - 4ac   (where a, b, c are real and rational), generally it is denoted by Δ , 

We obtain the following results
  1. If  Δ  >  0 and is a perfect square then the roots are rational and unequal.
  2. If  Δ  >  0 but not a perfect square then the roots are irrational and unequal.
  3. If  Δ  =  0 then the roots are real and equal.
  4. If  Δ <  0 then the roots are complex and imaginary.


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