3. Simplify the following expressions.
(a)3√-343
(b)(3√27)^(-2)
(c) 5√(32^3)
(d)(√2.25)^(-1)
4.Simplify the following expressions
(a) 25^(1.5)
(b) 81^(-0.75)
(c)(-125)^(2/3)
(d)[6^(-2)]^^0.5
Ans:3(a)-7
(b)1/9
(c)8
(d)2/3
4(a)125
(b)1/27
(c)25
(d)1/6
唔該列式教教我點計，多謝!
Form 4 maths questions about exponential and logarithm(1)
2008-10-18 7:31 am
回答 (2)
2008-10-18 8:19 am
✔ 最佳答案
3a)3√(-343) = (-343)^(1/3)
= -7
b) (3√27)^(-2)
= (27^(1/3))^(-2)
= 3^(-2)
= 1/9
c)5√(32^3)
= (32^(1/5))^3
= 2^3
= 8
d) (√2.25)^(-1)
= 1/(√2.25)
= 1 / 1.5
= 2/3
4a) 25^(1.5)
= 25^(3/2)
= (√25)^3
= 125
b) 81^(-0.75)
= 1/ 81^(3/4)
= 1/ 3^3
= 1/ 27
c) (-125)^(2/3)
= [(-125)^(1/3)]^2
= (-5)^2
= 25
d) [6^(-2)]^0.5
= 6^(-1)
=1/6
2008-10-18 8:16 pm
3a)
3√(-343)
= (-343)^(1/3)
= -7
b)
(3√27)^(-2)
= (27^(1/3))^(-2)
= 3^(-2)
= 1/9
c)
5√(32^3)
= (32^(1/5))^3
= 2^3
= 8
d)
(√2.25)^(-1)
= 1/(√2.25)
= 1 / 1.5
= 2/3
4a)
25^(1.5)
= 25^(3/2)
= (√25)^3
= 125
b)
81^(-0.75)
= 1/ 81^(3/4)
= 1/ 3^3
= 1/ 27
c)
(-125)^(2/3)
= [(-125)^(1/3)]^2
= (-5)^2
= 25
d)
[6^(-2)]^0.5
= 6^(-1)
=1/6
Hope I can help you.
3√(-343)
= (-343)^(1/3)
= -7
b)
(3√27)^(-2)
= (27^(1/3))^(-2)
= 3^(-2)
= 1/9
c)
5√(32^3)
= (32^(1/5))^3
= 2^3
= 8
d)
(√2.25)^(-1)
= 1/(√2.25)
= 1 / 1.5
= 2/3
4a)
25^(1.5)
= 25^(3/2)
= (√25)^3
= 125
b)
81^(-0.75)
= 1/ 81^(3/4)
= 1/ 3^3
= 1/ 27
c)
(-125)^(2/3)
= [(-125)^(1/3)]^2
= (-5)^2
= 25
d)
[6^(-2)]^0.5
= 6^(-1)
=1/6
Hope I can help you.
參考: my maths knowledge
收錄日期: 2021-04-19 20:33:34
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