Answer:
Solutions are 2, -1 + 0.5 sqrt10 i and -1 - 0.5 sqrt10 i
or 2, -1 + 1.58 i and -1 - 1.58i
(where the last 2 are equal to nearest hundredth).
Step-by-step explanation:
The real solution is x = 2:-
x^3 - 8 = 0
x^3 = 8
x = cube root of 8 = 2
Note that a cubic equation must have a total of 3 roots ( real and complex in this case). We can find the 2 complex roots by using the following identity:-
a^3 - b^3 = (a - b)(a^2 + ab + b^2).
Here a = x and b = 2 so we have
(x - 2)(x^2 + 2x + 4) = 0
To find the complex roots we solve x^2 + 2x + 4 = 0:-
Using the quadratic formula x = [-2 +/- sqrt(2^2 - 4*1*4)] / 2
= -1 +/- (sqrt( -10)) / 2
= -1 + 0.5 sqrt10 i and -1 - 0.5 sqrt10 i
Answer: Distance between line and point =
4√5 -3/2√10
Step-by-step explanation:
Distance between the line is
= √ ((9-0)²+(0+1)²)
= √ (89+1)
= √90
= 3√10
Half of the line = 3/2√10
Distance of one side of the line and the point.
= √((9-1)²+(0-4)²)
= √((8)²+(-4)²)
=√64+16
= √80
= 4√5
Distance between line and point =
4√5 -3/2√10
