Simplify the following expressions.
1) (Inx)^2+Inx/Inex
2) 2^(3-2x)．e^(x+2)=30
F.4 Maths
2010-04-29 6:02 am
回答 (1)
2010-04-29 6:11 am
✔ 最佳答案
1) (Inx)^2+Inx/Inex= (Inx)(Inx + 1) / In(ex)
= (Inx)(Inx + Ine) / In(ex)
= (Inx)(In(ex) / In(ex)
= Inx
2) 2^(3-2x)．e^(x+2)=30
In [ 2^(3-2x)．e^(x+2)] = In 30
In (2^(3-2x)) + In (e^(x+2)) = In 30
(3-2x) In 2 + (x+2) In e = In 30
(3-2x)In2 + x+2 = In30
(1 - 2In2)x + 3In2 + 2 = In30
x = (In30 - 3In2 - 2) / (1 - 2In2)
x = 1.75577
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