# pre-calculus

posted by suie

x^3e^x - 4e^x =0

1. Damon

e^x (x^3 - 4) = 0

e^x = 0
x = -oo

x^3 = 4

x = 4^(.333....)

Not sure if you do complex arithmetic

360/3 = 120
if so you also have two complex roots
one at +120 degrees and one at - 120
x = r (cos 120 + i sin 120)
x = 4^(1/3) ( -.5 + i sqrt3/2)
x = 4^.3333...(.5)(-1+isqrt 3)

and the other is
x = 4^.3333...(.5)(-1-isqrt 3)

2. suie

3. Reiny

If the equation is as you typed my money is riding with Damon.

4. suie

are u sure b/c the answers are from the book

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