A-Level Maths: A1-14 Proving the Cube Root of 2 is Irrational

[amadif]

I have a test on this tomorrow, this explanation was very helpful. Thanks!

[alicewu]

This is so much helpful than all the other explanations. clear and understandable, thank you!!

[James-qnrg]

very clear, this playlist will be very useful. Thank you.

[wtw]

Nice and clear explanation, thanks for the help.

[petasot]

Hello from Czechia! Thank you so much for this video ;)

[gracekas]

Simple explaination and easy to understand. Thank you

[zen]

Thank you for your wonderful explanation, but I'm confused, why do a and b having the common factors meaning that a/b is not a rational number? For example, 1/2 is a rational number, so as 10/20. However, you said that if a/b is not in the simplest form, then it is not a rational number. Is that meaning that 10/20 is irrational? Although it has the same value as 1/2?

[johnwang]

Just a suggestion: you can teach the rational root theorem and then use that to prove that all nth roots of integers that aren't nth powers are not rational. It's much cleaner, and the proof of the rational root theorem is actually very easy to understand.

[redroses]

How would you prove there are no pos integers, m and n, such that m^2 - n^2 = 6,

[yaseenshamsi]

Sir plz explain the proof of cube root of 4 instead of 2 because when I reach the step stating-"4 is a factor of a^3" then its become complicated because if I assume a=2 (which is an integer)then 4 will not be a factor of 'a' And we have already assumed that 'a' and 'b' are integers.

[ytjaisinhanope]

Is it applicable for all types of roots?

[nomrelol]

Very good explanation sir
Love from india

[durgashaktim]

You have divide8 by 2 then 4 come
If i said we have to find the cube root 6 then what we have to do

[shafzkay]

I said b cubed /b has a factor of 4 meaning it must be even. a and b are both even so a/b isn't in its simplest form so cube root of 2 is irrational.
Is that fine?