how many integer number between 3^3 and 4^3 ,where ^ is power
Answers
Answer:
There are 36 numbers between 3³ and 4³
Step-by-step explanation:
First we must know what 'between' here means.
Numbers between two integers is exclusive of the integers itself.
For ex:-
Numbers between 3 and 8 = 4, 5, 6, 7
See 3 and 8 is not included in the list
Also,
Number of integers between two integers a and b, where a > b = (a - b) - 1
For ex:- Numbers between 3 and 8 is,
(8 - 3) - 1 = 5 - 1 = 4
So, there are 4 numbers between 3 and 8
They are 4, 5, 6, 7.
Now,
We must find the integers between 3³ and 4³.
Now,
3³ = 27
4³ = 64
So,
The numbers between 64 and 27 = (64 - 27) - 1
= 37 - 1
= 36
Hence,
There are 36 numbers between 3³ and 4³
Now,
we can form a generalised formula for this purpose.
We know that, where a > b
a³ - b³ = (a - b)(a² + ab + b²)
Now,
For the number between a³ and b³
(a³ - b³) - 1 = [(a - b)(a² + ab + b²)] - 1
So,
The general formula is = [(a - b)(a² + ab + b²)] - 1
Brackets are just used to that you know what to do first.
Now, you might feel that this is unnecessary, but the truth is its not.
Here, We got a small number such as 3 and 4, but if they ask us about 32³ and 54³, its is pretty hard to calculate it in less time, that is where our general formula plays an important role.
Hope it helped and believing you understood it........All the best