2) if x^ (1/4) + x ^(-1/4) = 4, find the values of the following expressions.
a) 開方x + (1/開方x)
b) x + (1/x)
Thanks.
更新1:
3) Given log2= 0.301030 and log 3= 0.477121, find to 5 places of decimals log 1.2
f4 maths question (10 marks)
2007-10-31 2:28 am
1) if 9 ^ (1/h) = 11 ^ (1/k) = 99 , where h and k isn't equal to 0, determine the value of h + k without finding thhe values of h and k.
2) if x^ (1/4) + x ^(-1/4) = 4, find the values of the following expressions.
a) 開方x + (1/開方x)
b) x + (1/x)
Thanks.
2) if x^ (1/4) + x ^(-1/4) = 4, find the values of the following expressions.
a) 開方x + (1/開方x)
b) x + (1/x)
Thanks.
回答 (2)
2007-10-31 4:09 am
✔ 最佳答案
1) 9^(1/h)=99 (given)log9^(1/h)=log99
(1/h)log9=log99
h=log9/log99---(1)
&
11^(1/k)=99
log11^(1/k)=log99
(1/k)log11=log99
k=log11/log99---(2)
(1)+(2): h+k=log9/log99+log11/log99
=(log9+log11)/log99
=log99/log99
= 1
2a)x^(1/4)+x^(-1/4)=4
x^(1/2)+2+x^(-1/2)=16
x^(1/2)+x^(-1/2)=14
b)x+2+x^-1=196
x+1/x=194
3)log1.2=log3+log0.4
=log3+log4-log10
=log3+2log2-1
=0.477121+2(0.301030)-1
=0.07918(cor. to 5 d.p.)
參考: My Maths Knowledge
2007-11-04 3:07 am
1) 1
3) 0.07918
3) 0.07918
收錄日期: 2021-04-23 22:50:31
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https://hk.answers.yahoo.com/question/index?qid=20071030000051KK02647