Question

不如龜去

求解第15題，答案是4

年
15、試求函數f(x)=2(2*
2
3
) +
2 (2+ -
+2
——
4-Sur-9
x=1
+3的最小值為
2 [( ₂²^²= 3 ) ² + ( = ²*² = 3 ) ³ + 3 =
=2[f-3桿+六-3+27+3
-2 [A²+ = -3(A+)- ] +12
16、求(log25+log:25)(logs8+logs 8)的值
2
= (log 5 + ² = log₂ 5 ) × ( ²log2+ = - Joh
3 Dogg
= 500d 5 x 9 od ?
2(77)-6(A+岁) +12
=2[(4-21-6)+2
is (2)
Ans:x二年,入>>
= 2
2 (1++) ²-6 (A^2)+8
(=2(+)-2)+8-0
=2[(+3)+
-
2
15
2

Answer 1

✨ 最佳解答 ✨

qn

A + 1/A ≥ 2√[A×(1/A)] = 2
A + 1/A - 3/2 ≥ 1/2
2[(A+1/A)-3/2]²+7/2 ≥ 2×(1/2)²+7/2 = 4