Function and limit mcq

Zeeshan 01 · 2017-04-05 18:31:47

Post #14

bobbym · 2017-04-05 19:17:46

Okay, what do you not understand?

Zeeshan 01 · 2017-04-06 01:51:03

I want to say eq of circle why not implicit function..

Bob · 2017-04-06 02:05:11

Zetafunc's formal definition and the vertical line test both come down to a simple test: for any x is there a unique y? For the circle most x values give two values of y so not a function.

I need to look again at your quadratic. At first sight it doesn't make sense to me. back shortly.

later edit: If a quadratic has a positive x^2 term then it is U shaped and therefore has a finite minimum. As x tends to + or - infinity y will tend to infinity so there is no finite maximum.

If, however, the x^2 term is negative, then it is upsidedown U shaped so it has a single finite maximum.

I recommend you try out some possible quadratics using the function grapher. While there try y = √ (4 - x^2). you see you only get half a circle.

Bob

iamaditya · 2017-04-06 23:45:05

Zeeshan 01 wrote:

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!!!!!!

Sorry for the late reply but you may visit this site:https://brilliant.org/wiki/maximum-valu … -equation/

Zeeshan 01 · 2017-04-07 02:48:37

It is saying that max value is -b÷a
Is it CORRECT? ?

iamaditya · 2017-04-07 19:51:36

You can jot the value of -b/a instead of x in ax²+bx+c and can see it yourself.

zetafunc · 2017-04-07 20:34:09

Your maximum would have to either be a stationary point or infinite. Have you tried differentiating your quadratic?

Bob · 2017-04-07 21:12:50

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

Zeeshan 01 · 2017-04-08 02:41:17

I know quadratic formula but what is line of symmetry? ?

Bob · 2017-04-08 06:41:22

Another name would be a mirror line.

http://www.mathsisfun.com/geometry/symm … hapes.html

Bob

Zeeshan 01 · 2017-04-08 16:17:39

Hmm thx!!

iamaditya · 2017-04-09 00:30:56

bob bundy wrote:

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

Hmmm, but as far as I know, the max and min value of a quadratic polynomial is when the value of x is

. Check the link above.

Bob · 2017-04-09 07:24:14

I agree. That's what I said.

Bob

Math Is Fun Forum

#26 2017-04-05 18:31:47

Re: Function and limit mcq

#27 2017-04-05 19:17:46

Re: Function and limit mcq

#28 2017-04-06 01:51:03

Re: Function and limit mcq

#29 2017-04-06 02:05:11

Re: Function and limit mcq

#30 2017-04-06 23:45:05

Re: Function and limit mcq

#31 2017-04-07 02:48:37

Re: Function and limit mcq

#32 2017-04-07 19:51:36

Re: Function and limit mcq

#33 2017-04-07 20:34:09

Re: Function and limit mcq

#34 2017-04-07 21:12:50

Re: Function and limit mcq

#35 2017-04-08 02:41:17

Re: Function and limit mcq

#36 2017-04-08 06:41:22

Re: Function and limit mcq

#37 2017-04-08 16:17:39

Re: Function and limit mcq

#38 2017-04-09 00:30:56

Re: Function and limit mcq

#39 2017-04-09 07:24:14

Re: Function and limit mcq

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