Answer:
Step-by-step explanation:
what do you need help with
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
Pythagoras theorem: leg 1 squared + leg 2 squared = hypotenuse squared
In the diagram, the triangle has angles 90 and 45. So the other angle in the triangle must be 45 degrees as well. (180 - 90 -45 = 45)
This means it is an isosceles triangle (since two angles are the same), so the two legs have the same length.
So we can say that length of leg1 = x, and the length of leg2 also equals x
Now let's use pythagoras' theorem:
leg1 = x
leg2 = x
hypotenuse = 16
x^2 + x^2 = 16^2
2x^2 = 16^2
2x^2 = 256
x^2 = 128
x = √(128)
x = 8√2
