1. Find the square root of 2 and 8. Add the answers together and multiply this second answer by itself. This should equal 18.
2.(Part 1) Find the square root of 3. Take the answer away from 2 and multiply this second answer by itself. I’ll call that A.
(Part 2) Find the square root of 3. Multiply that by 4 and subtract the answer from 7. I’ll call that b.
If the equation is correct then A should be equal to B.
I suppose it was a test that asking you to insert some math symbols will make the sums correct, right ?
If you try to calculate them with a calculator you will see that the square root of 2 plus the square root of 8, all at the power of 2 give you 18. I suppose the other it’s a the same.
The actual calc is fine except how the hell do you work out a square root without a calculator. I guess back in the dim and distant past they could do it but I haven’t a clue!
David – that is a WOW from me! I will of course be telling D that maths like this is invaluable in many aspects of day-to-day life and as such she should listen carefully to her teachers π
Sorry for poor english, i’m from Russia
bravo:)) i was afraid that nobody will remebered this school rule. It’s the elementary case of using Isaak Newton(right or no?) binom
I haven’t tried this out yet but here goes:
1. Find the square root of 2 and 8. Add the answers together and multiply this second answer by itself. This should equal 18.
2.(Part 1) Find the square root of 3. Take the answer away from 2 and multiply this second answer by itself. I’ll call that A.
(Part 2) Find the square root of 3. Multiply that by 4 and subtract the answer from 7. I’ll call that b.
If the equation is correct then A should be equal to B.
I’ll go try them and see if they work now π
I suppose it was a test that asking you to insert some math symbols will make the sums correct, right ?
If you try to calculate them with a calculator you will see that the square root of 2 plus the square root of 8, all at the power of 2 give you 18. I suppose the other it’s a the same.
Maybe i’m missing what is your real question.
Sorry – I should have said: This is part of a NON-calculator maths test.
Yep it works. How close depends on how many decimal places you work to:
1.
(1.4142+2.8284)x(1.4142+2.8284)=18
2.
(2-1.7321)x(2-1.7321)=0.072 (A)
7-(4×1.7321)=0.072 (B)
A=B
π
“This is part of a NON-calculator maths test. ”
JESUS!!!!
The actual calc is fine except how the hell do you work out a square root without a calculator. I guess back in the dim and distant past they could do it but I haven’t a clue!
(a+b)^2 = a^2 + b^2 + 2ab
(SQR(2)+sqr(8))^2 = 2+8+2*(sqr(2)*sqr(8)), but sqr(8) = 2*sqr(2)
so 2+8+2*(sqr(2)*sqr(8)) = 2+8+2(sqr(2)*2*sqr(2)) = 10+2*(4)
= 18
(a-b)^2 = a^2+b^2-2ab
=> (2-sqr(3))^2 = 4+3-2*2*sqr(3) = 7-4*sqr(3)
David – that is a WOW from me! I will of course be telling D that maths like this is invaluable in many aspects of day-to-day life and as such she should listen carefully to her teachers π
http://flickr.com/photos/geeksmakemehot/71494695/
First one
#2
http://flickr.com/photos/geeksmakemehot/71496404/
Here is a great site on square root rules…
http://math.usask.ca/emr/roots.html
When you start trying to work out square roots of negative numbers then things start getting interesting π
You make my brain hurt.
Sorry for poor english, i’m from Russia
bravo:)) i was afraid that nobody will remebered this school rule. It’s the elementary case of using Isaak Newton(right or no?) binom
Guter Aufstellungsort, ja!
putang ina ng mga tao dto