Function and limit mcq

Zeeshan 01 · 2017-04-04 20:32:44

X^2+y^2=4 is function or not a function
Question 2 The function f(x)=ax^2+bx+x has Maximum value if a>0 ,a <0, a>1,a>2
Question 3 The linear function f(x)=ax+b is identity function if a=b=0, a=b=1, (a=1,b=0)

Last edited by Zeeshan 01 (2017-04-04 21:09:54)

iamaditya · 2017-04-04 21:13:30

X^2+y^2=4 is function or not a function

It is a functiion.

Question 2 The function f(x)=ax^2+bx+x has Maximum value if a>0 ,a <0, a>1,a>2

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-∞

Question 3

???

iamaditya · 2017-04-04 21:14:34

Question 3 The linear function f(x)=ax+b is identity function if a=b=0, a=b=1, (a=1,b=0)

What is the question here?

bobbym · 2017-04-04 21:15:50

Hi;

Is that not a circle?

iamaditya · 2017-04-04 21:19:40

No, I think.

bobbym · 2017-04-04 21:27:50

x^2 + y^2 = 4 I meant.

iamaditya · 2017-04-04 21:36:27

Yeah, that is the equation of a circle. You are right, bumpkin.

bobbym · 2017-04-04 21:41:30

You will have to explain to him why it is a function even though it fails the vertical line test.

iamaditya · 2017-04-04 21:46:31

A function is an expression of a variable or a relation between 2 variables.

bobbym · 2017-04-04 21:50:04

Hi;

Watch this video to get a bit more:

https://www.youtube.com/watch?v=Lv8Bt9Z1ohM

iamaditya · 2017-04-04 21:52:10

Hmm, good video...but I knew what is a function.

bobbym · 2017-04-04 21:53:00

It says that is not a function.

iamaditya · 2017-04-04 21:58:13

Why isn't it a function. It is a function of x with degree 2.

zetafunc · 2017-04-04 21:58:22

Bobbym is right: it isn't a function. Formally, a function is a rule which uniquely maps an element of its domain to an element of its image. In other words, if and are sets, then is a function if for any , there is a unique such that . You can clearly see that that isn't the case here: look at where gets mapped to, for instance.

bobbym · 2017-04-04 21:58:58

Hi;

That is not the definition of a function. You are describing an equation.

zetafunc · 2017-04-04 22:00:54

Moreover, that is precisely what the point of the vertical line test is: a function can be many-to-one, but it can never be one-to-many, which the circle is.

zetafunc · 2017-04-04 22:03:03

Zeeshan 01 wrote:

Question 3 The linear function f(x)=ax+b is identity function if a=b=0, a=b=1, (a=1,b=0)

Said differently, for which do we have ?

bobbym · 2017-04-04 22:03:53

I would say it is not a function but some people are arguing that a circle is just two semicircles thrown together and both of the semicircles are functions. But when it comes to the equation x^2 + y^2 = 4 I would say it is not a function. Do you agree?

zetafunc · 2017-04-04 22:05:51

bobbym wrote:

But when it comes to the equation x^2 + y^2 = 4 I would say it is not a function. Do you agree?

Yes, I agree.

iamaditya · 2017-04-04 22:29:35

Hmm, now I understand.

Zeeshan 01 · 2017-04-05 00:51:37

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!!!!!!

Zeeshan 01 · 2017-04-05 01:37:11

Now Any one also explain about why eq of circle is not a function

zetafunc · 2017-04-05 02:04:32

Did you see post #14?

Zeeshan 01 · 2017-04-05 02:44:07

You can clearly see that that isn't the case here: look at where gets mapped to, for instance.

PLease Explain this liNE????

bobbym · 2017-04-05 02:47:11

Please point out the post where that comes from.

Math Is Fun Forum

#1 2017-04-04 20:32:44

Function and limit mcq

#2 2017-04-04 21:13:30

Re: Function and limit mcq

#3 2017-04-04 21:14:34

Re: Function and limit mcq

#4 2017-04-04 21:15:50

Re: Function and limit mcq

#5 2017-04-04 21:19:40

Re: Function and limit mcq

#6 2017-04-04 21:27:50

Re: Function and limit mcq

#7 2017-04-04 21:36:27

Re: Function and limit mcq

#8 2017-04-04 21:41:30

Re: Function and limit mcq

#9 2017-04-04 21:46:31

Re: Function and limit mcq

#10 2017-04-04 21:50:04

Re: Function and limit mcq

#11 2017-04-04 21:52:10

Re: Function and limit mcq

#12 2017-04-04 21:53:00

Re: Function and limit mcq

#13 2017-04-04 21:58:13

Re: Function and limit mcq

#14 2017-04-04 21:58:22

Re: Function and limit mcq

#15 2017-04-04 21:58:58

Re: Function and limit mcq

#16 2017-04-04 22:00:54

Re: Function and limit mcq

#17 2017-04-04 22:03:03

Re: Function and limit mcq

#18 2017-04-04 22:03:53

Re: Function and limit mcq

#19 2017-04-04 22:05:51

Re: Function and limit mcq

#20 2017-04-04 22:29:35

Re: Function and limit mcq

#21 2017-04-05 00:51:37

Re: Function and limit mcq

#22 2017-04-05 01:37:11

Re: Function and limit mcq

#23 2017-04-05 02:04:32

Re: Function and limit mcq

#24 2017-04-05 02:44:07

Re: Function and limit mcq

#25 2017-04-05 02:47:11

Re: Function and limit mcq

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