Validity of checking solutions by plugging into original exercise

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lookagain

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From this thread:

Jomo said:
You are correct. Good job! But why bother us when you can plug in the value for x on the left hand side of the equation and see if you get 9?
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That's not logical. A correct answer for x doesn't mean the steps leading up to it are correct.

The student wasn't "bothering" us. It was our place to tell the student if his steps were correct, wrong, and/or
needed adjustments.
 
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stapel said:
Just to clarify, the original poster is not being regarded as having been "annoying" anybody.
The previous reply is meant as a humorous way of pointing out a very good way of checking one's own work,
something which can be an absolute lifesaver on tests! ;)
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And my reply must have gone over certain people's heads. It is not enough to substitute a value at
the end of the solution into the original equation to see if it checks. If there is fudging, canceling of errors, etc.,
then it is irrelevant if the final answer checks in the original equation.

This student wanted to know if he had done it correctly. Also, hypothetically, just because this student asks about
the correctness of one solution, that doesn't mean the student has found all of the possible solutions.
 
lookagain said:
From this thread:



That's not logical. A correct answer for x doesn't mean the steps leading up to it are correct.

The student wasn't "bothering" us. It was our place to tell the student if his steps were correct, wrong, and/or
needed adjustments.
Click to expand...
Look here lookagain, one job as a teacher, tutor, forum poster ... is to bring a student up to a level of some maturity. This student has been on the forum for awhile and I want this student to start standing on his own. If you have a problem with that, then that's your problem. Why not spend time helping students rather than searching posts of people who have commented on your ridiculous posts and then posting something negative about their posts?
As I said in response to your private message, where you said that that you will go after me, bring on the battle. Just remember that it you against about 4-5 of us.
 
stapel said:
Just to clarify, the original poster is not being regarded as having been "annoying" anybody. The previous reply is meant as a humorous way of pointing out a very good way of checking one's own work, something which can be an absolute lifesaver on tests! ;)
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Yes, Stapel, you are absolutely correct about why I made my post. Maybe, lookagain did not realize that I initially stated that Abel was correct and said good job.
 
lookagain said:
And my reply must have gone over certain people's heads. It is not enough to substitute a value at
the end of the solution into the original equation to see if it checks. If there is fudging, canceling of errors, etc.,
then it is irrelevant if the final answer checks in the original equation.

This student wanted to know if he had done it correctly. Also, hypothetically, just because this student asks about
the correctness of one solution, that doesn't mean the student has found all of the possible solutions.
Click to expand...
How on earth are you going to get a nine (9, 8+1, nueve, 18/2) place decimal answer and make a mistake. Did you not read that I wrote You are correct. Good job! (or am I assuming too much when I say that you read?)
 
Jomo said:
How on earth are you going to get a nine (9, 8+1, nueve, 18/2) place
decimal answer and make a mistake. [sic]Did you not read that I wrote You are correct. Good job!
(or am I assuming too much when I say that you read?) <---- I read it the first time, and
you made no point by mentioning it here.
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After all of my redundant explanations, I see that unfortunately you are still unable to
argue correctly regarding this and understand why your posts don't make sense.

You typed to the student "You are correct. Good job!" That was sufficient. Nothing is to follow about
"bothering" a tutor, because the student *was not doing it*.
As soon as you as typed after your first two sentences (above), Jomo, you were starting to
negate what you had just typed, and you were contradicting yourself, too.

When the student asked if he had done it correctly, that means all of the steps.

- - -- - - - - - - - - --- - - - - - - - -- - - - - - - -- - - - - - - - - - - --- -- - --- - --


Here is a hypothetical situation to contrast.

If the student had presented those steps to us and stated that his instructor
had stated that all of the student's steps were correct, or it was the case that
the instructor gave the student the steps and that the steps were all true,
and the student had asked how would he know if the x-value at the end was
correct, then we could tell the student he should substitute the x-value
back into the original equation to see if there is close agreement
decimal-wise.
 
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Denis said:
After I solve something, if I can see if my answer is correctby substituting in original,
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1) Your answer being correct is irrelevant if the steps are wrong.

2) Just because your answer may check, you may have missed other correct answers from case 1) above.

Jomo said:
Look here lookagain, one job as a teacher, tutor, forum poster ... is to bring a student up to a
level of some maturity. This student has been on the forum for awhile and I want this student to start standing on his own.
Nope, the student was the mature one. You were immature by wrongly bringing the word "bother"into it.

If you have a problem with that, then that's your problem. No, I have a problem with you. You're a confirmed liar
against me here, *and* you can't argue correctly.

Why not spend time helping students Oh, but I do. That's another of lies.

rather than searching posts of people who have commented on your ridiculous posts and then posting something
negative about their posts? As I said in response to your private message, where you said that that you will go after me,
[righteously so as you lied about me] bring on the battle.

Just remember that it you against about 4-5 of us.
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No, it is me against you. And I'm dealing with you, now a confirmed liar, someone who misrepresents, can't argue properly, and works off of emotionalism.
 
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Ishuda said:
It [redundancy mentioned in another quote] is not the only thing you have said that I agree with
but I certainly do agree that you are redundant in many cases.
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Ishuda (according to lookagain) said:
I have acted the stupid fool for taking the above out of context.
As a result, lookagain will righteously redouble his efforts and go after any of my posts for the slightest
of infractions. I was foolish for the posting of the above without regard for the consequences.
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Denis said:
Agree; but you missed my point.
I first substitute to see if correct: THAT IS MY 1ST STEP.

Following that, IF I want to check my steps, that's my decision;
I may or may not.

So I guess I'm really saying:
my 1st step is always check by substitution. End.
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When you had an instance in some other problem in the forum, Denis, where you incorrectly divided both
sides by a variable, you lost some information. You didn't have that solution to even substitute to see if it
was correct.

You didn't know that you were supposed to be considering another solution as a candidate.
 
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lookagain said:
...
Ishuda said:
It [redundancy mentioned in another quote] is not the only thing you have said that I agree with
but I certainly do agree that you are redundant in many cases.
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Ishuda [B said:
(according to lookagain) [/B]]
I have acted the stupid fool for taking the above out of context.
As a result, lookagain will righteously redouble his efforts and go after any of my posts for the slightest
of infractions. I was foolish for the posting of the above without regard for the consequences.
Click to expand...
...
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lookagain,

I can understand you being unable to understand a conversation here, make up what you think it means, and then blame someone else for your interpretation and apparent lack of understanding what the conversation meant. I mean, after all, you are just that kind of person and no one should expect you to behave better than you are, IMO, capable of behaving.

Of course, you may not agree with my opinion and express that difference. I know there is a good probability that you will misunderstand what I said anyway in your answers but I do wish you would quit misquoting me. Once or maybe twice would be forgivable because of your apparent inability to always understand basic concepts. But I would think that if you quote some one, it should be what was said and not one of your normal flights of fancy where you believe what you think is correct is correct rather than being only what you think in your confused perception of the world.
 
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This is absolutely ridiculous...... I am locking thread
 
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