Maths: Exponential?
回答 (1)
2017-11-23 1:16 pm
x^(1/2)+1/√x=4
(√x+1/√x)^2=x+2+1/x=4^2=16 ---> x+1/x=14 ---> 2x+2/x=2(x+1/x)=28 ....Ans
(x+1/x)^2=x^2+2+1/x^2=14^2=196 ---> x^2+1/x^2=194
x^3+1/x^3=(x+1/x)(x^2-1+1/x^2)=(14)(194-1)=2702
(√x+1/√x)^2=x+2+1/x=4^2=16 ---> x+1/x=14 ---> 2x+2/x=2(x+1/x)=28 ....Ans
(x+1/x)^2=x^2+2+1/x^2=14^2=196 ---> x^2+1/x^2=194
x^3+1/x^3=(x+1/x)(x^2-1+1/x^2)=(14)(194-1)=2702
收錄日期: 2021-04-24 00:50:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20171123032919AAVQ1Wx