Sunday, August 25, 2013
Sunday, August 11, 2013
How to Solve Quadratic Equation
How to Solve Quadratic Equation
What is the meaning of solving Quadratic Equation?
Answer is quite simple "In sample manner finding the roots of equation"
Now what are roots of quadratic Equations.
Roots are those values of "x" at which the equation is satisfied for e.g.
2x2 -8x + 5 = 0
roots of this equations means those values of x at which this equation is satisfied
let x1 and x2 be those values of x
then when we put these values in equation it must satisfy it
L.H.S=R.H.S
Solving Equation
First we have to find the nature of roots.For this we have to find discriminant
Roots can be real,equal and complex
Following Equation is the genric quadratic equation
ax2+bx + c = 0
Discriminant or D is given by
D = b2- 4ac
If
D > 0 two roots are real
D = 0 roots are equal
D < 0 two roots are complex
For e.g.
Case 1:
for the equation
2x2 -8x + 5 = 0
Compare it with generic quadratic equation ax2+bx + c = 0
a= 2 ,b= -8,c= 5
so D = (-8)2 -4*2*5
= 64 -40
=24
24 >0
s o it has two real roots
Case 2:
Now consider this equation
x2 -2x + 5 = 0
so a= 1,b= -2,c = 5
D= (-2)2 -4*1*5
= 4 -20
= -16
Since -16 <0 font="" nbsp=""> 0>
so D is negative it has two complex roots
Case 3 :
x2 -2x + 1 = 0
a=1,b=-2,c=1
D = (-2)2 -4*1*1
= 4-4
=0
Since D=0 so it has two equal roots
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