Cant Solve This | Mathematics | Page 1

candid oysterBOT Feb 18, 2024, 8:58 AM

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rancid ridge Feb 18, 2024, 8:59 AM

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woe

verbal sparrow Feb 18, 2024, 9:01 AM

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Can you show what you've tried?

rancid ridge Feb 18, 2024, 9:02 AM

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Exactly what the problem told me to do lol

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verbal sparrow Feb 18, 2024, 9:02 AM

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Well, I mean your attempt at a solution.

rancid ridge Feb 18, 2024, 9:02 AM

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verbal sparrow Well, I mean your attempt at a solution.

The first screenshot is my attempt.

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Theres not much else I can do.

verbal sparrow Feb 18, 2024, 9:03 AM

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rancid ridge The first screenshot is my attempt.

Using Desmos is not your attempt.

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Please try it yourself.

rancid ridge Feb 18, 2024, 9:03 AM

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My professor does not teach us how to solve it ourselves rather having us use technology. Her words not mine ¯_(ツ)_/¯

verbal sparrow Feb 18, 2024, 9:04 AM

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rancid ridge My professor does not teach us how to solve it ourselves rather having us use te...

Well, do you know the usual process of bringing a system to RREF?

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Just usual Gauss' method.

rancid ridge Feb 18, 2024, 9:05 AM

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verbal sparrow Well, do you know the usual process of bringing a system to RREF?

Im familiar with it as the "show me an example" shows the process.

verbal sparrow Feb 18, 2024, 9:06 AM

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rancid ridge Im familiar with it as the "show me an example" shows the process.

Alright. If you're familiar with it, try it.

versed citrus Feb 18, 2024, 9:06 AM

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this is sufficient

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w is a free variable

rancid ridge Feb 18, 2024, 9:07 AM

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versed citrus this is sufficient

I guarantee you, that it is not the right answer.

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I tried that ;-;

verbal sparrow Feb 18, 2024, 9:07 AM

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Hm...

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Let me try.

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I'll put it in a spoiler so you can try it, too.

versed citrus Feb 18, 2024, 9:07 AM

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if that is the rref then that is correct

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lemme check

rancid ridge Feb 18, 2024, 9:08 AM

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Well with the other variations of the same problem, the answer is not that.

versed citrus Feb 18, 2024, 9:09 AM

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it's correct

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(x,y,z,w) = (w, 75-w, 40-w, w), where w is arbitrary

rancid ridge Feb 18, 2024, 9:11 AM

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Its definitely not expecting it.

versed citrus Feb 18, 2024, 9:11 AM

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that is not possible

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the system you start with has rank 3

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no matter how you fill this out, it's rank 4

rancid ridge Feb 18, 2024, 9:14 AM

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¯_(ツ)_/¯

drowsy radish Feb 18, 2024, 9:14 AM

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Screencap the problem and send it to your instructor with the remark: technology disagrees

rancid ridge Feb 18, 2024, 9:14 AM

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LOL

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I am somewhat ahead of you on that.

versed citrus Feb 18, 2024, 9:15 AM

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versed citrus (x,y,z,w) = (w, 75-w, 40-w, w), where w is arbitrary

at any rate, the parametrised solution is this

rancid ridge Feb 18, 2024, 9:17 AM

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I did it ONE time and got the right solution but that was a one time thing clown_sad

versed citrus Feb 18, 2024, 9:17 AM

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if you do it correctly you'll get it right every time

rancid ridge Feb 18, 2024, 9:17 AM

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I did it exactly the same way every time

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One time somehow it was right then the rest was wrong.

versed citrus Feb 18, 2024, 9:18 AM

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rancid ridge Its definitely not expecting it.

if you are expected to change rank 3 into rank 4, then that's not possible

rancid ridge Feb 18, 2024, 9:19 AM

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Heres the system of equations based on the problem

verbal sparrow Feb 18, 2024, 9:19 AM

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Here's what I got. Everything seems to be fine.

rancid ridge Feb 18, 2024, 9:19 AM

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rancid ridge Heres the system of equations based on the problem

and its augmented matrix

versed citrus Feb 18, 2024, 9:19 AM

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see he gets the same thing i did

verbal sparrow Feb 18, 2024, 9:19 AM

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Hey, spoilers! 😅

rancid ridge Feb 18, 2024, 9:20 AM

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verbal sparrow Hey, spoilers! 😅

Dont worry, it's not what was expected anyway because technology disagrees.

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The calculator agrees with your solution but not with the problem.

versed citrus Feb 18, 2024, 9:20 AM

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rancid ridge Heres the system of equations based on the problem

yes and I already checked the rref you found is correct

verbal sparrow Feb 18, 2024, 9:20 AM

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rancid ridge Dont worry, it's not what was expected anyway because technology disagrees.

What do you mean? I got the same result as Desmos.

rancid ridge Feb 18, 2024, 9:20 AM

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verbal sparrow What do you mean? I got the same result as Desmos.

The question itself disagrees.

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Because the problem itself is wrong.

verbal sparrow Feb 18, 2024, 9:20 AM

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rancid ridge The question itself disagrees.

How so?

rancid ridge Feb 18, 2024, 9:21 AM

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Scroll thru the thread.

versed citrus Feb 18, 2024, 9:21 AM

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dont

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basically, the automated check is not correctly set up

drowsy radish Feb 18, 2024, 9:21 AM

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The question disagrees with the template for answering.

verbal sparrow Feb 18, 2024, 9:21 AM

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Oh, is it supposed to have a unique solution?

versed citrus Feb 18, 2024, 9:21 AM

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it can't noway

verbal sparrow Feb 18, 2024, 9:21 AM

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In that case yeah, the problem isn't set up correctly.

rancid ridge Feb 18, 2024, 9:21 AM

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This whole thread is just us realizing that the problem is wrong

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lol

verbal sparrow Feb 18, 2024, 9:21 AM

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That's fine, it happens.

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Although, that just means there are infinitely many solutions with one degree of freedom.

versed citrus Feb 18, 2024, 9:22 AM

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@rancid ridgewrite to your course supervisor

verbal sparrow Feb 18, 2024, 9:22 AM

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That also works, I guess.

versed citrus Feb 18, 2024, 9:22 AM

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assuming this is homework or some such

verbal sparrow Feb 18, 2024, 9:23 AM

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As w, x, y, z need to all be nonnegative, we have {w, x, y, z} = {t, 75 - t, 40 - t, t} for 0 ≤ t ≤ 40.

rancid ridge Feb 18, 2024, 9:23 AM

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rancid ridge Feb 18, 2024, 9:24 AM

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rancid ridge

this is the entire problem and how its wrong and such.

verbal sparrow Feb 18, 2024, 9:24 AM

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rancid ridge

I suggest you also post your attempt, so that the teacher at least knows that you've also tried it.

rancid ridge Feb 18, 2024, 9:26 AM

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according to what the rref states.

verbal sparrow Feb 18, 2024, 9:27 AM

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What's this?

rancid ridge Feb 18, 2024, 9:27 AM

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This

verbal sparrow Feb 18, 2024, 9:28 AM

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Oh. Well, yeah.

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As we discussed above, we get {w, x, y, z} = {t, 75 - t, 40 - t, t}.

rancid ridge Feb 18, 2024, 9:28 AM

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verbal sparrow As we discussed above, we get {w, x, y, z} = {t, 75 - t, 40 - t, t}.

yes thats what I got too

versed citrus Feb 18, 2024, 9:29 AM

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so what's the problem

rancid ridge Feb 18, 2024, 9:29 AM

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I didnt say there was

verbal sparrow Feb 18, 2024, 9:29 AM

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versed citrus so what's the problem

Well, I assume the problem wanted a unique solution. Guess it wasn't set up correctly.

versed citrus Feb 18, 2024, 9:30 AM

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let's just solve the problem as stated, not start speculating

verbal sparrow Feb 18, 2024, 9:30 AM

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Oh, we already did.

rancid ridge Feb 18, 2024, 9:31 AM

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Im creating a thread in the class. So everyone is aware of it and they don't go crazy as I did 🙏

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Okay, to anyone who is still here and willing to help

Can someone explain this problem to me.

How does one get the system of equations? Why is the answer D) ?

verbal sparrow Feb 18, 2024, 9:41 AM

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Hm...
Well, we can take x + y as 3 and multiply it by 8 at the top. Not sure why 3x + 2y has to be 8 at the same time, though.

rancid ridge Feb 18, 2024, 9:51 AM

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verbal sparrow Hm... Well, we can take x + y as 3 and multiply it by 8 at the top. Not sure why...

Why x+y as 3?

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I kinda understand 3x+2y=8 (from the game card)

verbal sparrow Feb 18, 2024, 9:54 AM

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rancid ridge Why x+y as 3?

Then we can make 24 as 3*8.

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What I don't really get is why 3x + 2y has to be 8 at the same time, though.

rancid ridge Feb 18, 2024, 9:54 AM

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verbal sparrow Then we can make 24 as 3\*8.

I thought that too but clearly its not right

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Because of this

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Am i just being given weird problems lol

verbal sparrow Feb 18, 2024, 9:57 AM

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Yeah, this one is a bit weird, to be honest.

drowsy radish Feb 18, 2024, 9:58 AM

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We have to make use of all 4 numbers, namely 8, 9, x+y and 3x+2y, to form 24 algebraically

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In addition, x and y are constrained to be single-digit positive integers

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For part (a), it can be conveniently observed that options A and C fail the constraints on x and y by subtracting both sides among the equations

rancid ridge Feb 18, 2024, 9:59 AM

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For the second parts of each a and b i did this

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I wrote code to solve it in order to speed up the process. (obviously wont be done in exams and such)

verbal sparrow Feb 18, 2024, 10:00 AM

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drowsy radish We have to make use of all 4 numbers, namely 8, 9, x+y and 3x+2y, to form 24 alg...

Ohh, we have to use all of them. I see.

drowsy radish Feb 18, 2024, 10:01 AM

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similarly, by observing the difference between equations for option B, x must be 1 and y must be 2, which contradicts with either equation.

rancid ridge Feb 18, 2024, 10:03 AM

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verbal sparrow Ohh, we have to use all of them. I see.

This I understood.

verbal sparrow Feb 18, 2024, 10:03 AM

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How do we make 24 from 3, 8, 8 and 9, though?

drowsy radish Feb 18, 2024, 10:03 AM

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3*(9-8/8)

rancid ridge Feb 18, 2024, 10:04 AM

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hence testOne

verbal sparrow Feb 18, 2024, 10:05 AM

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Ohh, I see.

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I've never been good at problems like these, to be honest...

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I don't really like problems where brute force is the only way.

drowsy radish Feb 18, 2024, 10:06 AM

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It's my go-to cooldown game when ending a tutoring session :D

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Making 24

rancid ridge Feb 18, 2024, 10:07 AM

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But how do i even get 3 for the first equation. x+y=3

drowsy radish Feb 18, 2024, 10:07 AM

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We draw a random quadruple of poker cards and play with them

rancid ridge Feb 18, 2024, 10:08 AM

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Like how do i know for sure which system of equation is the right one.

drowsy radish Feb 18, 2024, 10:08 AM

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You just check the solution sets for violations of the given constraints

rancid ridge Feb 18, 2024, 10:10 AM

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drowsy radish For part (a), it can be conveniently observed that options A and C fail the cons...

Could you visually represent this?

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Im still slightly confused.

drowsy radish Feb 18, 2024, 10:11 AM

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For A, 2x+y = 1, but x and y must be positive integers so the sum should be at least 3

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Similarly for C

young latchBOT Feb 18, 2024, 11:08 AM

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rancid ridge Feb 18, 2024, 11:08 AM

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+close

#Cant Solve This