Question

I tried FOIL'ing this one but its not working very well :( http://i.imgur.com/bdla7.png

Answer 1

http://www.wolframalpha.com/input/?i=%28sqrt5-sqrt2%29%5E2

Answer 2

THis is what it's saying.
\[(\sqrt{5} - \sqrt{2})^{2} = \sqrt{5}(\sqrt{5} - \sqrt{2}) - \sqrt{2}(\sqrt{5} - \sqrt{2})\]Can you solve this?

Answer 3

5-2sqrt(10) + 2
7-2sqrt(10)

Answer 4

first = sqrt5*sqrt5=5
outer = -sqrt2sqrt5
inner = -sqrt2sqrt5
last = -sqrt2(-sqrt2)
5-2sqrt5sqrt2+2
7 - 2sqrt(10)

Answer 5

make sence?

Answer 6

@zzr0ck3r how is sqrt5*sqrt5=5 ? Im sorry, but my brain is pretty fried right now.

Answer 7

sqrt(5) = 5^(1/2)
sqrt(5) * sqrt(5) = (5^(1/2))*(5^(1/2)) = (5*5)^(1/2) = sqrt(25)

Answer 8

think about sqrt(4)*sqrt(4)

Answer 9

or sqrt(9)*sqrt(9) this is no proof but it shold convince you:)

Answer 10

\[(\sqrt{5} - \sqrt{2})^{2} =(\sqrt{5} - \sqrt{2})(\sqrt{5} - \sqrt{2}) = \sqrt{5}(\sqrt{5} - \sqrt{2}) - \sqrt{2}(\sqrt{5} - \sqrt{2}) \]

Answer 11

(5*5)^.5 is giving me 11.18. I think im even more confused now.

Answer 12

think distributive property

Answer 13

sqrt5 = 5^(1/2) this is just proboly something with your calculator

Answer 14

http://www.wolframalpha.com/input/?i=%2825%29%5E%281%2F2%29

Answer 15

probably*

Answer 16

ti-83's dont do this properly?

Answer 17

I dont understand how sqrt5*sqrt5=5 is 5 though since the square root of 5 is 2.236... Can someone draw a solution for me so i can understand how you did it?

Answer 18

multiply 2.236... by 2.236...

Answer 19

the sqrt(x)*sqrt(x) = x for all real numbers

Answer 20

for all numbers

Answer 21

2.236 is a aprx, the number sqrt(5) could never be written, sort of like pie

Answer 22

what is sqrt4*sqrt4 and what is sqrt9*sqrt9 what is sqrt(36)sqrt(36) what is sqrt(144)*sqrt(144)?

Answer 23

so i get to here: \[\sqrt{25}-\sqrt{10}-\sqrt{6}+\sqrt{4} = 7 - \sqrt{16}\]
Where did i go wrong?

Answer 24

which becomes 7 - 4 = 3. Which is certainly not the correct answer.

Answer 25

\[\sqrt{5}\] means the number that, when you multiply it by itself, you get five
that is the meaning of the symbol \(\sqrt{a}\)
so it must be the case that \(\sqrt{5}\times \sqrt{5}=5\) and that is the only meaning given to \(\sqrt{5}\)

Answer 26

also \(\sqrt{2}\times \sqrt{2}=2\) for exactly the same reason

Answer 27

on the other hand you cannot add and subtract roots by adding or subtracting inside the radical. for example \(\sqrt{a}+\sqrt{b}\neq \sqrt{a+b}\) unless either \(a\) or \(b\) is zero

Answer 28

so then \[7 - \sqrt{10} - \sqrt{6}\] So how do i go from that to the answer?

Answer 29

\[(\sqrt{5}-\sqrt{2})^2=5-2\sqrt{5}\sqrt{2}+2\] as
\[(a-b)^2=a^2-2ab+b^2\] then only thing left to do is write
\[7-2\sqrt{10}\]

Answer 30

there is no \(\sqrt{6}\) if the original problem was \((\sqrt{5}-\sqrt{2})^2\)

Answer 31

square root 5 is the number that multiplied by itself will give you 5 therefor sqrt5*sqrt5 = 5

Answer 32

So you use a2−2ab+b2 instead of FOIL?

Answer 33

a^2-2ab+b^2 is the exact same things as (a-b)^2 foiled out

Answer 34

Ah, now i understand. Thank you so much guys :)

Answer 35

woo hoo:)