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- This topic has 43 replies, 17 voices, and was last updated 13 years ago by yitayningwut.
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November 9, 2011 8:36 pm at 8:36 pm #600425yitayningwutParticipant
Half of A plus half of B equals half of A and B together.
Is there a rule with a name for this fact?
November 9, 2011 8:50 pm at 8:50 pm #826340nitpickerParticipantThe distributive property of multiplication over addition
November 9, 2011 8:53 pm at 8:53 pm #826341The FrumguyParticipantIt is the distributive law – remember good ole ninth grade algebra?
November 9, 2011 8:58 pm at 8:58 pm #826342am yisrael chaiParticipantfactoring.
1/2 A + 1/2 B = 1/2(A+B)
You are factoring out the common term, 1/2.
======================================================
The reverse process is the distributive property, distributing the 1/2 to each term: 1/2(A+B)=1/2 A + 1/2 B
November 9, 2011 9:04 pm at 9:04 pm #826343DavkaNikMemberthe Law of Association
see: http://www.mathsisfun.com/associative-commutative-distributive.html
November 9, 2011 9:20 pm at 9:20 pm #826344MDGParticipantDistributive Property.
.5 A + .5 B = .5 (A+B)
or
C*A + C*B = C*(A+B)
November 9, 2011 9:24 pm at 9:24 pm #826345BaalHaboozeParticipantoooooooh….high school maaaath…..bringing back baaaaad memories……I’m outta here!
November 9, 2011 9:37 pm at 9:37 pm #826346charlie brownMemberI believe its the distributive property. .5A + .5B = .5(A+B)
November 9, 2011 9:38 pm at 9:38 pm #826347MiddlePathParticipantI believe that is called the distributive property:
x(a+b)= xa+xb. So in your example, x=1/2.
Oops, looks like others got there first. Sorry for repeating.
November 9, 2011 9:57 pm at 9:57 pm #826348GumBallMemberEEEEWWW! GROSS!! lets talk abt sumfin better and more appetizing!! YUM!! I LOVE IC CREAM!! WHATS UR BET FLAVOR??
November 9, 2011 10:01 pm at 10:01 pm #826349charlie brownMemberAYC is correct, the rest of us who wrote distributive are wrong.
November 9, 2011 10:01 pm at 10:01 pm #826350Queen BeeMemberIt’s the Distributive Property.
Example: 1/2(5) + 1/2(2) = (5+2)/2. Doing that math, both sides should equal 3.5.
November 9, 2011 10:03 pm at 10:03 pm #826351am yisrael chaiParticipantAssociation would be
(A + B) + C = A + (B + C)
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Commutative is
(A + B) = C = (B + A) + C
or
A+B = B+A
November 9, 2011 10:32 pm at 10:32 pm #826352nitpickerParticipantno ayc is not exactly correct .
this is the distributive property.
the factoring also depends on distributive property.
distributive is a law not a process so it is not correct to
refer to the reverse.
whether you remove or create the parenthesis,
you are still applying the distributive property.
done for this thread.
November 9, 2011 10:46 pm at 10:46 pm #826353wanderingchanaParticipantMods!! I was promised there would be no math in the CR! Please delete this post immediately!
November 9, 2011 11:10 pm at 11:10 pm #826354yitayningwutParticipantThank you so much everyone! It came up in learning, that’s why I put it in the Beis Medrash, lol.
November 9, 2011 11:12 pm at 11:12 pm #826355am yisrael chaiParticipant“AYC is correct, the rest of us who wrote distributive are wrong.”
Thank you, charlie brown. It was quite uncomfortable being the sole unpopular opinion here. (At least I wasn’t berated for it…guess I’m not over that other experience yet, sigh)
November 9, 2011 11:20 pm at 11:20 pm #826356Sam2ParticipantFactoring and the distributive property are the same thing. Factoring works because it uses the distributive property.
November 9, 2011 11:50 pm at 11:50 pm #826357charlie brownMemberwandering, just for that your punishment is that you have 3 minutes to figure out the circumference of a circle with a diameter or 4″
🙂
November 10, 2011 2:53 am at 2:53 am #826358am yisrael chaiParticipantIn 1/2 A + 1/2 B = 1/2(A+B), you are not distributing anything. You are factoring out the 1/2.
In the reverse 1/2(A+B)=1/2 A + 1/2 B, you are distributing out the 1/2 and removing parentheses.
November 10, 2011 2:59 am at 2:59 am #826359GumBallMemberWho likes Mint Chocolate chip ice cream!! HEAVEN!!
November 10, 2011 3:05 am at 3:05 am #826360am yisrael chaiParticipantGumball, so in your example, if you split half the Mint Chocolate chip ice cream with person A and half of it with person B….
November 10, 2011 3:18 am at 3:18 am #826361GumBallMemberAHHHHH!!! LOL!!!!! omg u crack me up in 2 half! lol!!!!!
November 10, 2011 6:07 pm at 6:07 pm #826362charlie brownMemberThank you, charlie brown. It was quite uncomfortable being the sole unpopular opinion here.
You’re very welcome.
(At least I wasn’t berated for it…guess I’m not over that other experience yet, sigh)
You’re lucky its bein hazmanim otherwise Bar Shatya may have called you a dolt!
November 12, 2011 11:31 pm at 11:31 pm #826363am yisrael chaiParticipantyitayningwut
“It came up in learning, that’s why I put it in the Beis Medrash, lol.”
very curious where in learning this came up…
November 13, 2011 2:21 am at 2:21 am #826364yitayningwutParticipantam yisrael chai –
Lol, I was waiting to see if anyone would pick up on that.
Here’s what happened.
Background: If someone tovels in a mikvah and there is a chatziza on ??? of his body, it is a chatzitza mid’oraisa (provided that he doesn’t want it to be on him). Anything else is only mid’rabannan or not a problem.
There is a machlokes between the Ge’onim and the Rambam about how to define ???. The Ge’onim held that the body and the hair are judged separately. That is, if the chatzitza covers ??? of the body but not ??? of the hair, it is a chatzitza. If it covers ??? of the hair and not ??? of the body, it is also a chatzitza. The Rambam disagrees and says there is no such thing. There is the body together with the hair and that’s it, if ??? of everything has a chatzitza, it is a problem; if not – even though there is a chatzitza on ??? of one – it is not a problem.
Apparently in this machlokes the Rambam is meikil and the Ge’onim are machmir. Says one of the acharonim, there is one case where the Rambam will be machmir and the Ge’onim will be meikil: When you have a ????? of hair and a ????? of the body but together they equal ??? of the body with the hair! Argued my Rosh Chabura, this is impossible!! No ????? plus a ????? can ever equal a ??? of both together!! It took him some time to convey his point to the chabura, but at the end of the day everyone realized what he meant. I just thought knowing the name of this law might help in explaining it to someone else in the future. 🙂 🙂
November 13, 2011 2:05 pm at 2:05 pm #826365charlie brownMemberyitayningwat – did anyone come up with pshat in that acharon? Which acharon was it?
November 13, 2011 4:26 pm at 4:26 pm #826366wanderingchanaParticipantcharlie brown – my eyes glazed over and it’s taken me 3 days to recover!
November 13, 2011 5:17 pm at 5:17 pm #826367yitayningwutParticipantCharlie – The Sfas Emes. No one had p’shat.
November 14, 2011 4:57 am at 4:57 am #826368charlie brownMemberwanderingchana, LOL!! You’ll be let off the hook this time but make sure to do your math homework tomorrow!
November 14, 2011 9:16 pm at 9:16 pm #826369Pashuteh YidMemberLet me take a stab at pshat here. When we talk of a chatzita in hair, it can be that it is tied up in knots. When we talk about a chatzitza in the body, it can be like mud.
Let us argue that the waist is the midpoint.
Suppose that up until just below the waist, a person is covered in mud. Suppose that above the waist, a miyut of hair is knotted up. However, when you add the amount of (square inches of) the person covered with mud, to the amount that has knotted hair, the person now has a chatzitza on rov of his body. The Rambam may say this is a chatzitza, while the geonim would say since each type separately has only a miyut, it is not a chatzitza.
November 14, 2011 11:11 pm at 11:11 pm #826370supergirl613MemberCan i ask another math question? this is it
3s=4(s-6)+2
I have a math test soon, and i’m gonna fail if I don’t know this answer quick! Could someone please help me out?
November 14, 2011 11:39 pm at 11:39 pm #826371charlie brownMembersupergirl613:
3s=4(s-6)+2
3s=4s-24+2
3s = 4s-22
-4s -4s
________________
-s = -22
s=22
Got it?
November 14, 2011 11:46 pm at 11:46 pm #826372am yisrael chaiParticipantThe idea is to simplify, simplify, simplify!
3s=4(s-6)+2
distribute the 4:
3s=4s-24+2
combine the numbers:
3s=4s-22
subtract 4s from both sides, so that you have all “s”‘s on one side of the equation and all numbers on the other side:
-1s= -22
divide by -1 (on both sides of the equation) so that you have “s” on its own, resulting in s=something
s=22
=======================
Check:
3s=4(s-6)+2
3(22) = 4(22-6)+2
66 = 4(16) +2
66 = 64 +2
66 = 66
November 15, 2011 1:16 am at 1:16 am #826373observanteenMemberBoy, supergirl, you made me do some math… Haven’t done any in a looong time!
I think it’s called “Inverse Operation”. The idea is to isolate the ‘s’, thus finding the value of ‘s’ (as CB and AYC explained above). Good luck!
November 15, 2011 1:43 am at 1:43 am #826374GumBallMemberWhats the Pythagorean Theorom?? OMG!!
November 15, 2011 1:45 am at 1:45 am #826375supergirl613MemberThank you both a lot, but Charlie Brown how did you get -4s=4s
and AYC how did you do the check?
I’m sorry I”m making you go crazy, but I”m having a really hard time!
November 15, 2011 1:53 am at 1:53 am #826376taking a breakMemberPythagorean theorem is A squared + B squared = C squared. its used for right triangles IIRC
example: a right triangle with 3 sides, one side is 3″, one is 4″ and the longest is 5″.
3*3 + 4*4 = 5*5
9+16=25
25=25
(i took geometry a long time ago. this correct? LOL)
November 15, 2011 1:54 am at 1:54 am #826377yitayningwutParticipantPashuteh Yid –
I don’t see how you are answering the question. The Rambam doesn’t hold you need rov of the body, he holds you need rov of the (body + hair). How can you ever get there with a mi’ut of the body and a mi’ut of the hair?
November 15, 2011 2:19 am at 2:19 am #826378observanteenMemberSupergirl: You check by inserting the number (in this case, 22) where the s was, and you see if it makes sense.
Also, CB didn’t write -4s = -4s, he just subtracted 4s from both sides.
Good luck on your test!
November 15, 2011 3:27 am at 3:27 am #826379supergirl613MemberAHHH!!! Thanks guys loads!!!! I may just pass my test thanks to you!!!!!
November 15, 2011 4:35 am at 4:35 am #826380Pashuteh YidMemberWithout seeing the Rambam or the acharon inside, I am assuming that hair and body do not add. Parts of the body are covered by hair, and parts by skin. The whole equals one body. Therefore the Rambam could not really mean the way you understand.
November 15, 2011 10:21 pm at 10:21 pm #826381GumBallMembertaking a break-O Man!! U got it!! thanx a TON!!
November 15, 2011 11:16 pm at 11:16 pm #826382yitayningwutParticipantPashuteh Yid –
The hair is not the body. The part of the body that is covered by the hair is the body, not the hair. The Ge’onim hold there are two individual halachic entities here. The Rambam holds there is one. Look up the Rambam if you want – Mikvaos 2:15.
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