Flag Algebra> trick...
question mark

is there anyone who can explain me the completing the square method in quadratic equation............

DEEPAK SINGH PARIHAR , 15 Years ago
Grade 11
anser 1 Answers
Rohith Gandhi

Last Activity: 15 Years ago

Dear Deepak,

First recall the algebraic identities

displaymath62

We shall use these identities to carry out the process called Completing the Square. For example, consider the quadratic function

displaymath64

What can be added to yield a perfect square? Using the previous identities, we see that if we put 2e=8, that is e=4, it is enough to add tex2html_wrap_inline70 to generate a perfect square. Indeed we have

displaymath72

It is not hard to generalize this to any quadratic function of the form tex2html_wrap_inline74 . In this case, we have 2e=b which yields e=b/2. Hence

displaymath80

 

Example: Use Complete the Square Method to solve

displaymath82

Solution.First note that the previous ideas were developed for quadratic functions with no coefficient in front of tex2html_wrap_inline84 . Therefore, let divide the equation by 2, to get

displaymath86

which equivalent to

displaymath88

In order to generate a perfect square we add tex2html_wrap_inline90 to both sides of the equation

displaymath92

Easy algebraic calculations give

displaymath94

Taking the square-roots lead to

displaymath96

which give the solutions to the equation

displaymath98

 

We have developed a step-by-step procedure for solving a quadratic equation; or, in other words, an algorithm for solving a quadratic equation. This algorithm can be stated as a formula called Quadratic Formula

Please feel free to post as many doubts on our discussion forum as you can. If you find any question
Difficult to understand - post it here and we will get you the answer and detailed solution very quickly. We
are all IITians and here to help you in your IIT JEE preparation.


All the best Deepak !!!




Regards,

Askiitians Experts

Rohith Gandhi P

Provide a better Answer & Earn Cool Goodies

Enter text here...
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments


Ask a Doubt

Get your questions answered by the expert for free

Enter text here...