Math People- Help, Urgent!

[Legolas]

no, and i know english lol- im only in an 8th grade advanced class and my teacher expects us to know things perfectly an hour after he teaches them, not even thorougly enough

[Lamsey]

xy=4

therefore

x = 4/y

therefore

(4/y)^2 + 4y^2 = 16

which is

16/(y^2) + 4y^2 = 16

which is

16 + 4y^4 = 16y^2

which is

4y^4 - 16y^2 + 16 = 0

which is

y^4 - 4y^2 + 4 = 0

which is

(y^2 - 2)^2 = 0

which is

y^2 - 2 = 0

which is y = root 2

therefore when y = root 2, x = (4/root 2)


so the answer is x = (4/root 2) and y = root 2.

[Lamsey]

Originally posted by Legolas@15 March 2004 - 01:16
no no, those are sposed to exponents

They're indices, not exponents.

[Legolas]

thanks a lot lamsey- are u a college professor or something? u know your stuff

[LSA]

Originally posted by Lamsey@14 March 2004 - 20:24
xy=4

therefore

x = 4/y

therefore

(4/y)^2 + 4y^2 = 16

which is

16/(y^2) + 4y^2 = 16

which is

16 + 4y^4 = 16y^2

which is

4y^4 - 16y^2 + 16 = 0

which is

y^4 - 4y^2 + 4 = 0

which is

(y^2 - 2)^2 = 0

which is

y^2 - 2 = 0

which is y = root 2

therefore when y = root 2, x = (4/root 2)


so the answer is x = (4/root 2) and y = root 2.

m4d skillz!

[Lamsey]

First year university student. Oh, and it's half one in the morning.

[4play]

somebody has a late start monday then.

i thought you were doing english at uni

[Lamsey]

Originally posted by 4play@15 March 2004 - 01:34
somebody has a late start monday then.

i thought you were doing english at uni 

MEng Computer Science

[4play]

a masters hey, /me adds your email to my list of people i can bug for help.

[Lamsey]

Originally posted by 4play@15 March 2004 - 01:40
a masters hey, /me adds your email to my list of people i can bug for help.

No, I'm doing... um... a PhD in History of Turnips, that's it!