How can the professor's claim be valid? (divisibility)

[Steven G]

Suppose n=7²*3 = 147
Clearly 7²|n

7³\(\displaystyle \nmid\)n
n\(\displaystyle \neq\)7³m
n\(\displaystyle \neq\)7²7m
n\(\displaystyle \neq\)7²c
7²\(\displaystyle \nmid\)n
But 7²|n
I see where the error is. The problem is that this video I was watching basically says just that (in my opinion)
The link to the video is here . Please watch from 39:30 for just a few seconds.

 

[blamocur]

I agree with you. I could not understand a word in the lecture, but the attached screenshot seems to match your post. All she is proving is that [imath]c_2[/imath] cannot be represented as as [imath]p^1 c_1[/imath], not that [imath]n\neq p^r \cdot c_2[/imath].

 

[Dr.Peterson]

Suppose n=7²*3 = 147
Clearly 7²|n

7³\(\displaystyle \nmid\)n
n\(\displaystyle \neq\)7³m
n\(\displaystyle \neq\)7²7m
n\(\displaystyle \neq\)7²c
7²\(\displaystyle \nmid\)n
But 7²|n
I see where the error is. The problem is that this video I was watching basically says just that (in my opinion)
The link to the video is here . Please watch from 39:30 for just a few seconds.

It seems to me that she failed to write down (or to say in English) any quantifiers, without which what's written is meaningless. "Not equal to" is particularly tricky that way: Does it mean "is never equal, for any value of the variables", or "is not equal for these particular values", or what?

Since the last line seems to be a definite conclusion, and is false, she appears to be making a mistake; does she then use that conclusion? (And can you understand a word she says? I can't even tell if it's meant to be English.)

 

[Steven G]

Its strange, at least to me, that she chooses to speak in English even though she is from India and her viewers are from India as well (It's clear to me from the comments that these commenters are from India).
I listened to her whole video and got better at understand her but I didn't under a lot of what she said.
I need to view the video again to see if she uses that (wrong) conclusion.

Thanks for looking at the video, I appreciate your help.

 

[blamocur]

Its strange, at least to me, that she chooses to speak in English even though she is from India and her viewers are from India as well

Long time ago I learned from an Indian colleague that there are zillions of different languages in India besides English and Hindi. Is English the Lingua Franca of India?

 

[Steven G]

I was wondering the same thing. Thanks for the information.

 

[khansaheb]

Is English the Lingua Franca of India?

Sort of! I am from northern part of India. When I visit south India - I use English to make myself understood.

I had the similar experience when I came to USA as a student (1972). I had very difficult time understanding spoken english - hillbilly, Cajun, Tex-mex ..... all sorts.