How many integers 1 0 0 ≤ n ≤ 1 0 0 0 are there such that n is rational?
If you do not know what an rational number is, you can read Root 2 is irrational .
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Can you explain your thinking step by step?
1 0 0 0 ≈ 3 1 . 6 2 2 isn't an integer, so how did you arrive at an integer value of 22?
what do u mean by "sqrt"?
I think it is the best for solving the math .Thank you :)
The highest square number till 1000 is 31^{2}=961.So there are 31 square numbers lesser than 1000. And there are 9 square numbers lesser than 100. 31-9=22. Therefore,the value of n is 22
10^2 = 100, 32^2 = 1024 >1000. So, the number of n is : 31-10+1 = 22.
3 1 − 1 0 + 2 = 2 2 .
Log in to reply
WHY DID YOU DID THIS?!?!?!?!?!?!
Log in to reply
Because if n = x is a rational <=> n = x^2. And 100<n<1000 <=> 100<x^2<1000
Sorry. I'm wrong. It 31-10+1 = 22. Sorry again and thanks your comment
The square root of 1000 = 31.6227766
Rounding it down, the perfect square closest to 1000 would be 31*31 = 961
You could attempt 32*32 = 1024 to confirm this.
The root of any integer squared would produce a rational answer.
i.e: 15*15=225 thus root of 225 = 15 (rational)
i.e: 10*10 = 100 thus root of 100 = 10 (rational)
In this case, an irrational answer occurs when the root of a number doesn't produce an integer
i.e: root of 30 = 5.477 (irrational)
i.e: root of 2 = 1.4142 (irrational)
Starting from 1 to 1000,
there are now values 1 to 31 {1, 2, 3, ..., 31} which can produce rational roots after being squared (refer to 2nd line).
We currently have 31 different integers.
Now to eliminate the answers between 1 to 99.
The square root of 99 = 9.949874371
Rounding it down, the perfect square closest to 99 would be 9*9 = 81
So we have values 1 to 9 {1, 2, 3, ..., 9} to be eliminated from our initial pool.
Here, we've got 9 different integers.
Removing the 9 integers from our bigger pool of 31, 31-9 = 22
Our new set of integers now range from 10 to 31 {10, 11, 12, ..., 31} which consists of 22 different integers.
i.e: 10x10 = 100 & 31x31 = 961 (corresponds with the range for roots between 100 and 1000)
root(n) (smallest)=10 & root(n) (largest) = 31
Or
100<=n<=100 Taking square roots........
10<=root(n)<=31.622
for rational values 10<n<31
Problem Loading...
Note Loading...
Set Loading...
sqrt(1000)- sqrt(100) +1 =22