Questions   
Sort: 
 #1
avatar+429 
+1
Apr 11, 2018
 #3
avatar+429 
+1
Apr 11, 2018
 #9
avatar+2489 
+1

I guess I submitted my answer and got it right????

You guess you submitted your answer? Either you did or didn’t.

 

It is a bit wordy

No kidding; who’d ever notice?

 

although GingerAle I used the fact how you used your casework and how you organized them. 

Then you submitted my answer, not yours. Both of our answers cannot be correct.

 

 “...

Your casework to count the successes did work, but isn't the most efficient such approach as you noted.

I made no comment about efficiency

 

Your second case when counting the successes was not labeled correctly.

That was the fourth case, and it was corrected. This was an easy catch, if you had reviewed the work.

 

Also, it is a bit confusing to label the cases with bolded combinations, since some of those technically have the same value. Instead, you could mark them with a short description like "Exactly  numbers colored:" and so on."
 That was from AoPS???

 

WTF! My presentation is a concept based teaching post; it’s not something I would submit to an AoPS teacher/professor, or any teacher/professor. If you wanted to use my solution method, you should have reworded it, but not with your neurotic Sweet Polly pure piss encouragement preceding every number.

 

"My answer is spot on.  I can “prove” my answer is correct,"

-???

I completed the Monte Carlo simulations. As expected, it hovers near 1/3 using the “Grogg” selection method.  Randomly choosing to color or not to color numbers 1-6, gives a slight variation around a 25% probability for a factorific coloring, and the counts of colored numbers, from 0 to 6 tends toward a binomial distribution.  There are other interesting statistics based on various restrictions. 

 

And there's no need to be rude? Chill? pls?

Yes there is. You assaulted the senses of everyone who read your post. At least, those who are not on thorazine or have a natural version of it.indecision

 

 I'm sorry if it is not pleasing to you

You’re not, and that’s an understatement!

 

GA

Edit Corrected typo.

Apr 11, 2018
 #1
avatar+26387 
+3

Suppose that $f(x)$ is a linear function satisfying the equation $f(x) = 4f^{-1}(x) + 6$. Given that $f(1) = 4$, find $f(2)$.

 

 

\(\text{1. $f(x)$ is a linear function}\)

\(\begin{array}{|lrcll|} \hline f(x) =& ax +b && \quad & | \quad f(1) = 4 \\\\ f(1) =& a\cdot1 +b &=& 4 \\ & \mathbf{a +b} &\mathbf{=}& \mathbf{4 } \qquad &(1) \\ & \mathbf{a } &\mathbf{=}& \mathbf{4-b } \\ \hline \end{array} \)

 

\(\text{2. $f^{-1}(x)=\ ? $ }\)

\(\begin{array}{|rcll|} \hline f(x) &=& ax +b \\ y &=& ax +b \\ ax &=& y-b \quad & | \quad : a \\ x &=& \dfrac{y-b}{a} \quad & | \quad x \leftrightarrow y \\ y &=& \dfrac{x-b}{a} \\ \mathbf{f^{-1}(x)} &\mathbf{=}& \mathbf{\dfrac{x-b}{a}} \\ \hline \end{array}\)

 

 

\(\text{3. $f(x) = 4f^{-1}(x) + 6$ }\)

\(\begin{array}{|rcll|} \hline f(x) &=& 4f^{-1}(x) + 6 \quad & | \quad x = 1 \\\\ f(1) &=& 4f^{-1}(1) + 6 \quad & | \quad f(1) = 4 \qquad f^{-1}(1) = \dfrac{1-b}{a} \\ 4 &=& 4 \left(\dfrac{1-b}{a} \right) + 6 \quad & | \quad - 6 \\ -2 &=& 4 \left(\dfrac{1-b}{a} \right) \quad & | \quad \cdot a \\ -2a &=& 4 (1-b) \\ -2a &=& 4-4b \quad & | \quad +4b \\ 4b-2a &=& 4 \quad & | \quad : 2 \\ \mathbf{2b-a} & \mathbf{=}& \mathbf{2} \qquad &(2) \\ \hline \end{array}\)

 

 

\(\text{4. $a=\ ? \qquad b=\ ?$ }\)

\(\begin{array}{|rcll|} \hline 2b-a & = & 2 \quad & | \quad a = 4-b \\ 2b-(4-b) & = & 2 \\ 2b-4+b & = & 2 \\ 3b-4 & = & 2 \quad & | \quad +4 \\ 3b & = & 6 \quad & | \quad :3 \\ \mathbf{ b} & \mathbf{=} & \mathbf{2} \\\\ a &=& 4-b \\ a &=& 4-2 \\ \mathbf{ a} & \mathbf{=} & \mathbf{2} \\ \hline \end{array}\)

 

 

\(\text{5. $f(x)=\ ?$ }\)

\(\begin{array}{|rcll|} \hline f(x) &=& ax +b \quad & | \quad a=2 \qquad b = 2 \\\\ \mathbf{ f(x)} & \mathbf{=} & \mathbf{2x +2} \\ \hline \end{array}\)

 

 

\(\text{6. $f(2)=\ ?$ } \)

\(\begin{array}{|rcll|} \hline \mathbf{ f(x)} & \mathbf{=} & \mathbf{2x +2} \quad & | \quad x = 2 \\\\ f(2) & = & 2\cdot 2 +2 \\ \mathbf{ f(2)} & \mathbf{=} & \mathbf{6} \\ \hline \end{array}\)

 

 

laugh

Apr 11, 2018
 #8
avatar+8 
+1

I guess I submitted my answer and got it right???? It is a bit wordy cheeky

 

although GingerAle I used the fact how you used your casework and how you organized them. 

 

And there's no need to be rude? Chill? pls? 

 

Uh, This work did actually belong to me, although like I said, is wordy and not the most efficient way, :/

 

"You correctly used constructive counting within casework to count the number of factorific colorings and total number of colorings, then used these values to calculate the desired probability.

Your casework to count the successes did work, but isn't the most efficient such approach as you noted. Plus, it is hard to check some of your cases to ensure you found all of the successful colorings and did not miss any, although your method of "combining" smaller sets could have helped you do this. Can you think of a faster and simpler approach here? You may still need some form of casework, although not necessarily based on the number of blue numbers. There are other approaches that have fewer cases and less complex ways to count the successes within each case.

Your second case when counting the successes was not labeled correctly. Also, it is a bit confusing to label the cases with bolded combinations, since some of those technically have the same value. Instead, you could mark them with a short description like "Exactly  numbers colored:" and so on."
 That was from AoPS???

 

"My answer is spot on.  I can “prove” my answer is correct,"

-???

 

 

"I think I need powerful anti-nausea meds to wade through this irrelevant, wordy, neurotic swill. Jesus Christ! It’s amazing that someone far surpassed Mr. BB in pasting mathematically infused slop on this forum.  It’s interesting that someone can write reasonably tight LaTex code but doesn’t know how to implement its execution here; "

 

-Uh...Ok??? I'm sorry if it is not pleasing to you, but  ¯\_(ツ)_/¯ 

Apr 11, 2018

0 Online Users