Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

|
Options

Ricky
2005-12-16 15:08:41

"also (i, -2i) and (-i, 2i), whatever these complex thingys mean, I don't remember."

Every nth degree equation has n solutions.  Some solutions may be double roots (i.e. (x-1)(x-1) = 0).  The graph may only pass through the x-axis (where y = 0, which would be a solutions) less than n times.  When this occurs, you get an imaginary solution, which is what i is.

sirsosay
2005-12-16 14:56:29

Thank you!

John E. Franklin
2005-12-16 14:03:59

I get (-2,-1) and (2,1) by graphing a sketch.

And I guess majicWaffle is right,
also (i, -2i) and (-i, 2i), whatever these complex thingys mean, I don't remember.

MajikWaffle
2005-12-16 14:00:55

x^4 - 3x^2 - 4 = 0

(x^2 - 4)(x^2 +1) = 0

x^2 - 4 = 0                   x^2 + 1 = 0
x^2 = 4                        x^2 = -1
x = +- 2                       x = +- i

sirsosay
2005-12-16 13:05:17

xy=2 and x²-y²=3

I got y by itself then I got...

2/x = ±√(x²-3)

I'm stuck at 4 = x^4-3x²