12 第8章 指數函數與對數函數
類題 0 <
Mua 14 0 <k< do k>7 4(lt logak - B-lognk)
或>7
3
49
a Log
#JSU D= 4(1 + log,k)2 - 4 x 1'x (3 + log,k) > 0
EP (log,k) + (log,k) - 2 > 0 EP (log,k+2)(log, k – 1) > 0
得 logik <-2 或logyk >1,得0<k< 或>7
om
49
範例8
-
=
egoldy
r-S = 2
gol
ol
2
Aa,r)
=
gol
E r = log, a I s = log2b
gol & = 8 gol=
AB 斜率為
y = log2x
a-b
Egol
Fr-s=2(a - b)
B(b,s)
SOLO
AB = /(a - b)2 + (r-s)?
15
Sagolt
L18)901
=/(a - b)2 +4(a - b)
18
= 75 (b-a) = 75 golstad 1890
SE
.. b - a = 1.1 Ur- s = 2(a - b) = -2
Cool S&gol
EJ log2a - log2b = log2
18 gol
Sego
2-2 1,194a= b... 2
b
4 El Sol
Arvyolla
01
1
4
1 4
1 21 a =
"b .. (
3
3
V10 16
類題 15
5
75
f(2a) = log/(2a) = log 2 + log; a =-4 ... 1
--
Ion a=-6... 2
d.=-2
b
yol
a
gol
-
b
子,所求=(:,:)
-
3'3
go