Math Is Fun Forum

hi Zeeshan 01

It is possible to show that all quadratics have a line of symmetry, and that for ones of the form y = ax^2 + bx + c this will be a verttical line.

If we start with the quadratic formula for the two roots:

it should be obvious that the two roots are symmetrically placed either side of the line

so the maximum will not be at

as you ask in post 31

Bob

Hmm, you need to find the max. and min. value of a quadratic equation. The max value of a quadratic equation is as follows:
a>0-∞
a<0--D/4a
a>1-∞
a>2-∞

What is this how you do this???

And question 1 ans is it is not a function!!!!!!

hi iamaditya

It was a joke.  Mathematicians call numbers like Square Root (-1) imaginary numbers.  There's a whole branch of mathematics devoted to the study, properties and applications of such numbers.  Look here for a start:

http://www.mathsisfun.com/numbers/complex-numbers.html

They are called 'imaginary' because the imaginary number line is the image of the real number line.  This choice has unfortunately led to some ignorant folk laughing at mathematicians for believing in something that is imaginary.  When Isaac Asimov was ridiculed by one such critic, saying how can you have an imaginary number, he replied "Here's a piece of chalk; now hand me a half a piece of chalk."  His point was that all numbers have no actual existence; they are all just abstract concepts.  Take the number 3 for example.  You cannot have a three; you cannot hold it; you cannot see it.  All you see is the symbol we use to denote it.  Out of context, it has no existence of its own.  I have three children; but I have no three. 

Thank you Phro for your jokes.

Bob

one of the reasons you say I can not live without the forum.