The given equation is an exponential equation and we'll
solve it using the substitution technique.
We notice that
(3+2sqrt2)*(3-2sqrt2) = 3^2 -
(2sqr2)^2
(3+2sqrt2)*(3-2sqrt2) = 9 -
4*2
(3+2sqrt2)*(3-2sqrt2) = 9 -
8
(3+2sqrt2)*(3-2sqrt2) =
1
We'll raise to x power both
sides:
[(3+2sqrt2)*(3-2sqrt2)]^x =
1^x
(3+2sqrt2)^x*(3-2sqrt2)^x =
1
(3+2sqrt2)^x = 1 /
(3-2sqrt2)^x
We'll note (3+2sqrt2)^x =
t
t = 1 /
(3-2sqrt2)^x
(3-2sqrt2)^x =
1/t
We'll substitute in the given
equation:
t + 1/t = 34
t^2 + 1
- 34t = 0
t^2 - 34t + 1 =
0
We'll apply the quadratic
formula:
t1 =
(34+sqrt1152)/2
t1 =
(34+24sqrt2)/2
t1 = 17 +
12sqrt2
t2 = 17 -
12sqrt2
(3+2sqrt2)^x = 17 +
12sqrt2
lg (3+2sqrt2)^x = lg (17 +
12sqrt2)
x*lg (3+2sqrt2) = lg (17 +
12sqrt2)
x1 = lg (17 + 12sqrt2) / lg
(3+2sqrt2)
x2 = lg (17 - 12sqrt2) / lg
(3+2sqrt2)
No comments:
Post a Comment