since 3x^2 - x - 3 is not factorable, we will have to
solve the equation 3x^2 - x - 3 = 0 using the quadratic
formula.
the quadratic formula
is:
let ax^2 + bx + c = 0
x =
[-b + sqrt(b^2 - 4ac)]/2a or x = [-b - sqrt(b^2 -
4ac)]/2a
with the equation 3x^2 - x - 3 = 0, we
get:
a = 3, b = -1, c =
-3
using this, substitution gives us the following
expressions for x:
x(1) = [-(-1)+sqrt((-1)^2 -
4(3)(-3))]/2(3)
= [1+sqrt(1 +
36)]/6
= [1 +
sqrt(37)]/6
x(2) = [-(-1)-sqrt((-1)^2 -
4(3)(-3))]/2(3)
= [1-sqrt(1 +
36)]/6
= [1 -
sqrt(37)]/6
since x(1) and x(2) are the solutions to the
equation, let a = x(1) and b = x(2).
a =
[1+sqrt(37)]/6
a^2 =
{[1+sqrt(37)]/6}^2
=
[1+sqrt(37)]^2/6^2
=
[1+2sqrt(37)+sqrt(37)^2]/36
=
[1+2sqrt(37)+37]/36
=
[38+2sqrt(37)]/36
=
[19+sqrt(37)]/18
b =
[1-sqrt(37)]/6
b^2 =
{[1-sqrt(37)]/6}^2
=
[1-sqrt(37)]^2/6^2
=
[1-2sqrt(37)+sqrt(37)^2]/36
=
[1-2sqrt(37)+37]/36
=
[38-2sqrt(37)]/36
=
[19-sqrt(37)]/18
a^2 + b^2 = [19+sqrt(37)]/18 +
[19-sqrt(37)]/18
=
[19+sqrt(37)+19-sqrt(37)]/18
= [19 +
19]/18
=
38/18
= 19/9 or 2
1/9
No comments:
Post a Comment