Proof help

J

jbower

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Feb 28, 2020
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6
I am working on a proof, and I'm about halfway through and I have this, which I know to be true, but I need help in showing that it is true.

C(k+1,3) + C(k+1,2) = C(k+1,3)

Help from here would be appreciated, as I think I'm a little stuck...
 
Is C(n, i) the binomial coefficient? If it is, you should have said that. If not we will need to know what it means! Assuming this is the binomial coefficient what you have written isn't true at all!

Cancel the "C(k+1, 3)" from both sides to get C(k+1, 2)= 0 which certainly isn't true!

Please go back and check the statement or the problem.
 
jbower said:
I am working on a proof, and I'm about halfway through and I have this, which I know to be true, but I need help in showing that it is true.

C(k+1,3) + C(k+1,2) = C(k+1,3)

Help from here would be appreciated, as I think I'm a little stuck...
Click to expand...
Since you say this is your result halfway through, you must have made a mistake earlier. This is one reason we ask you to show the entire problem, as given to you, in addition to your work: We can catch mistakes you have made!

Or this may just be a typo, which we could have corrected if you showed the work.
 
Whenever you add two numbers and the answer is one of those numbers, then the other number better be 0.

I tell this to a 7th grader whom I tutor all the time!
 
Jomo said:
Whenever you add two numbers and the answer is one of those numbers, then the other number better be 0.

I tell this to a 7th grader whom I tutor all the time!
Click to expand...
(7th grader is Subhotosh..... ;))
 
Jomo said:
Actually he is still working towards that goal. He is trying but its going slowly. He is a difficult student.
Click to expand...
Slowly but surely, even the most difficult students will graduate under your guidelines.
 
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