Division

[Yuseph]

Yo,


Ok two questions. Thanks

- why does x goes into x3 only 2 times ? Why is the answer x2 and not x3 ?

- why does the 1st substraction give - x2y ?? And not + x2y ? Can you also explain why the 2nd substraction give xy2 instead of -xy2

Plz explain as if I was a 8y old kid.

 

[Deleted member 4993]

Yo,

View attachment 21132
Ok two questions. Thanks

- why does x goes into x3 only 2 times ? Why is the answer x2 and not x3 ?

- why does the 1st substraction give - x2y ?? And not + x2y ? Can you also explain why the 2nd substraction give xy2 instead of -xy2

Plz explain as if I was a 8y old kid.

- why does x goes into x3 only 2 times ?

What do you mean? Where did you see this!​

Why is the answer x2 and not x3 ?

x³/x = x² because​

​

x³ = x * x * x and​

​

x² = x * x​

- why does the 1st substraction give - x2y ?? And not + x2y ? - An 8 yr. old would surely know

0 - x²y = - x²y​

 

[Yuseph]

You re right. Thats obvious 3^3 / 3 = 3^2. I had 3/1 in mind thats why.

Now ive never seen anywhere than 0 minus sth equal a minus result. Since 0 is not taking away anything. Whats the explanation ?

 

[Dr.Peterson]

Now ive never seen anywhere than 0 minus sth equal a minus result. Since 0 is not taking away anything. Whats the explanation ?

Take an example: What do you get for 0 - 5?

You are taking 5 away from zero, not zero away from 5. Or, if you wish, you are moving 5 units to the left from zero on the number line. Do you end up at 5, or -5?

 

[Yuseph]

Its actually the author who confused me when he wrote x into x3 goes x2.
Put like that it should goes 3 times. x3 = x time x time x.
But thats x3 divided by x which is different.

Regarding 0 - x yeah my focus shut down after so many hours on math. Of course 0 - 5 will give -5

Turns out that as im writing this i saw the two others are even worse. Whats x into -x2y goes -xy. And x into xy2 goes y2. ?
He gave no theory about that.

 

[Deleted member 4993]

View attachment 21135

Its actually the author who confused me when he wrote x into x3 goes x2.
Put like that it should goes 3 times. x3 = x time x time x.
But thats x3 divided by x which is different.

Regarding 0 - x yeah my focus shut down after so many hours on math. Of course 0 - 5 will give -5

Turns out that as im writing this i saw the two others are even worse. Whats x into -x2y goes -xy. And x into xy2 goes y2. ?
He gave no theory about that.

I think you are not working out these example problems with "pencil & paper".

How do you expand x²y $\displaystyle \to \ \$ = x * x * y

If divide x²y by x $\displaystyle \ \ \to \ \$What do you get?

8 year olds should know that!!

 

[Yuseph]

Yea i guess my 7y old.nephew would have answered xy.
Nah i dont bother much i try to browse though it intuitively and pause only when i bump into sth that need special attention. Theres so much left. 30 more chapters.
But i do put all exercices on my onenote app. So thats pretty much the same.

 

[joshuaa]

for example, when the author says divide 3 into 5, he just means [MATH]\frac{5}{3}[/MATH]

 

[HallsofIvy]

View attachment 21135

Its actually the author who confused me when he wrote x into x3 goes x2.
Put like that it should goes 3 times. x3 = x time x time x.
But thats x3 divided by x which is different.

Regarding 0 - x yeah my focus shut down after so many hours on math. Of course 0 - 5 will give -5

Turns out that as im writing this i saw the two others are even worse. Whats x into -x2y goes -xy. And x into xy2 goes y2. ?
He gave no theory about that.

Probably the author foolishly assumed that by the time you were doing problems like this you would know what things like $\displaystyle x^3$, $\displaystyle x^2y$, and $\displaystyle xy^2$ meant! (And, please, if you don't want to use "tex" at least use ^ to indicate powers, x^3 and xy^2, and not "x3" and "xy2".)

$\displaystyle x^3$ means "x*x*x" so $\displaystyle \frac{x^3}{x}= \frac{x\cdot x\cdot x}{x}= x\cdot x= x^2$, $\displaystyle x^2y$ means x*x*y so $\displaystyle \frac{x^2y}{x}= \frac{x*x*y}{x}= x*y= xy$ and $\displaystyle \frac{xy^2}{x}= \frac{x*y*y}{x}= y*y= y^2$.

 

[Steven G]

for example, when the author says divide 3 into 5, he just means [MATH]\frac{5}{3}[/MATH]

or she