Question

Hi...
Last question and i can sleep peacefully :)
THANKS

Answer 1

\[\huge a= 2^{\frac{ 1 }{ 2 }} + 2^{\frac{ -1 }{ 2 }}\]
\[\huge b=2^{\frac{ 1 }{ 2 }} - 2^{\frac{ -1 }{ 2 }}\]
FIND
\[\huge a ^{3} + b ^{3}\]

Answer 2

lol someone randomly gave me a medal?

Answer 3

i know the formula for a^3 + b^3 btw

Answer 4

(a+b)(a^2-ab + b^2)

Answer 5

so, a+b=.. ?

Answer 6

its actually \( 2 \times 2^{1/2}\)

Answer 7

yea :)

Answer 8

ok, keep that as it is...
now try (a^2-ab + b^2) =... ?

Answer 9

same thing as 2^1/2 + 2^1/2

Answer 10

i worked out a^2 was 9/2 before

Answer 11

9/2 ?
just a second..

Answer 12

b^2 was also ummm 1/2

Answer 13

\((a^2-ab+b^2 )= (a^2-2ab+b^2)+ab = (a+b)^2+ab\)
you already know a+b

Answer 14

find ab

Answer 15

we know a+b = 2*2^(1/2)

Answer 16

ab = 3/2?

Answer 17

yes :)

Answer 18

would it be (a-b)^2 + ab? instead of (a+b)^2 + ab

Answer 19

sorry, my mistake

Answer 20

\((a^2-ab+b^2 )= (a^2+2ab+b^2)-3ab = (a+b)^2-3ab\)

Answer 21

so ill just work out (a^2-ab + b^2) manually?

Answer 22

wait but i dont think i done (a+b)^2

Answer 23

i was just trying to simplify...you can do that manually, but it'll become complicated...

Answer 24

(a+b)^2 would be 8?

Answer 25

yes.
ab = 3/2
so, -3ab = -9/2
and 8+9/2 =... ?

Answer 26

*8-9/2=..

Answer 27

7/2

Answer 28

so answer is (2^1/2 times 2 )(7/2)
Is it?

Answer 29

\(2 \times 2^{(1/2)} \times 7/2 =2^{(1/2)} \times 7 \)

Answer 30

ok thank you so much

Answer 31

these question confuse me so much :(

Answer 32

practice more.... all confusions will go away...

Answer 33

lol thats easy to say