Select the exclusion that fits best with this problem.

13x^6/51x^4

x = 0
x, y, z = 0
1 + y + y2, y = 0, 1 - y = 0
a, b = 0, a2+ ab + b2= 0
2x - 1 = 0, 4x2+ 2x + 1 = 0

Question

Select the exclusion that fits best with this problem.


13x^6/51x^4

x = 0
x, y, z = 0
1 + y + y2, y = 0, 1 - y = 0
a, b = 0, a2+ ab + b2= 0
2x - 1 = 0, 4x2+ 2x + 1 = 0

e.mccormick · Answer

OK, for $$\frac{13x^6}{51x^4}$$What could make it into an invalid answer?

anonymous · Answer

?

anonymous · Answer

and hi again :D

e.mccormick · Answer

Hi again.

"Select the exclusion" means things that would not give valid answers.

anonymous · Answer

ths one: a, b = 0, a2+ ab + b2= 0?

e.mccormick · Answer

Well, there is a huge clue in the fact that it does not have an a or b in it...

You have a fraction there, or rational equation.  What breaks any fraction?  The one type of division that they say is a big no-no, can't be done, does not exist... and so on.

anonymous · Answer

as always, you confuse me, lol

e.mccormick · Answer

LOL.  Well, how about this:
$$\frac{2}{0}$$Does that mean anyhting in math?

e.mccormick · Answer

Just try it in a calculator.  See what $2\div 0$ gets you.

anonymous · Answer

you can't divide by zero....it will open a wormhole to the gamma quadrant or something

anonymous · Answer

the exclusion rules:   no dividing by zero
no negative roots....$$\sqrt{x}$$ for x>=0
ln x?  x has to be greater than zero

e.mccormick · Answer

But kantalope, wormholes are fun!  They het you warp space time and all that!

anonymous · Answer

o-o back and again, whaaaaat?

anonymous · Answer

oh, yeah complex infinity when u divide 2 
by 0

e.mccormick · Answer

Yah.  So, when the bottom would be 0 it is mathematically bad.  That is what they want to know.

e.mccormick · Answer

When $\frac{13x^6}{51x^4}=\frac{13x^6}{0}$ it is to be excluded.  So, which answer does that?

anonymous · Answer

x=0?

e.mccormick · Answer

Yep!

anonymous · Answer

helpful as always, lol

e.mccormick · Answer

Well... I poke, I prod...  I try not to do more than clues.  Sometimes it works, sometimes not.

anonymous · Answer

lol, i think your tactic is confuse then answer

e.mccormick · Answer

No, no.  Math is progressive.  So I dig up old topics like 2/0 to indicate how this relates to the other topic!

anonymous · Answer

oh so it's confuse, help confuse now? xD

e.mccormick · Answer

It is called the Socratic Method.  A tried and true form of teaching!

anonymous · Answer

...so I am right :D

e.mccormick · Answer

http://www.stanford.edu/dept/CTL/cgi-bin/docs/newsletter/socratic_method.pdf

e.mccormick · Answer

Well, because there is an end goal, it is not pure Socratic Method, but the baseline idea is there.  Use questions to expose the core of the problem and related it to previously learned facts.

anonymous · Answer

......yes