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The Killer
04-28-2012, 11:29 AM
ok got a exam monday and cant do a few questions on revision sheet, plz explain how to do them:

1) find X when:
2x√8=2^x


2) evaluate
a) 3^-2

b)27^2/3

16^3/2

masterBB
04-28-2012, 11:37 AM
3^-2 equals 1 / 3^2
27^2/3 equals 3√(27^2)
16^3/2 equals 2√(27^3)

The Killer
04-28-2012, 11:38 AM
3^-2 equals 1 / 3^2
27^2/3 equals 3√(27^2)
16^3/2 equals 2√(27^3)
fancy explaining them? thanks

masterBB
04-28-2012, 11:41 AM
fancy explaining them? thanks

x ^ -y is the same as 1 / ( x ^ y)
x ^ z / y is the same y√(x^z)

The Killer
04-28-2012, 12:30 PM
x ^ -y is the same as 1 / ( x ^ y)
x ^ z / y is the same y√(x^z)

tyvm +rep

The Killer
04-29-2012, 05:30 PM
anyone know the answer to question one?

Rich
04-29-2012, 05:52 PM
Is that as in 2 multiplied by x, multiplied by √8, or 2 multiplied by the xth root of 8?

Cerylin
04-29-2012, 05:59 PM
If its 2√8= 2^x then you do
Log2√8=xlog2
Log2√8/2=x
x=5/2

If its 2x√8=2^x then i have no idea lol.

Endzior
04-29-2012, 06:14 PM
If its 2x * √8 = 2 ^ x then you have to know Lambert's W func. Not sure if it's properly written then, because that shit's is REAL business :) Of course you can always try to take those 2 functions on a graph and mark the places where they cross each other :

f(x) = 2 ^ x
g(x) = 4√2 * x

That's the only available solution I guess, judging by your age :) But it's still gonna be hard to get "exact" results. Peace!