∫ 4^x dx
Please show all the steps
Find the following integrals
2013-10-09 6:23 pm
回答 (2)
2013-10-09 8:46 pm
✔ 最佳答案
Please read:圖片參考：http://imgcld.yimg.com/8/n/HA00430218/o/20131009124554.jpg
2013-10-09 12:50:27 補充：
噢，唔好意思～
我答的時候其實先確定了無人作答所以才發表～
太巧合了～
其實也不是第一次有這種巧合～
不好意思～
^___^"
2013-10-09 8:41 pm
∫ 4^x dx
Let y = x⁴
lny = xln4
d(lny)/dy = (ln4)(dx/dy)
(1/y) = (ln4)(dx/dy)
dx = dy/(y)(ln4)
∫ 4^x dx = ∫ [(y)/(y)(ln4)]dy
= ∫ [1/(ln4)]dy
= (y/ln4) + C
= (4^x)/ln4 + C
2013-10-09 13:46:32 補充：
Sorry, 一時手快，打錯了，應該是 Let y = 4^x。
樓下易睇好多，睇樓下啦！
2013-10-09 14:17:20 補充：
YOU ARE WELCOME。你 D 答案好睇好多。
Let y = x⁴
lny = xln4
d(lny)/dy = (ln4)(dx/dy)
(1/y) = (ln4)(dx/dy)
dx = dy/(y)(ln4)
∫ 4^x dx = ∫ [(y)/(y)(ln4)]dy
= ∫ [1/(ln4)]dy
= (y/ln4) + C
= (4^x)/ln4 + C
2013-10-09 13:46:32 補充：
Sorry, 一時手快，打錯了，應該是 Let y = 4^x。
樓下易睇好多，睇樓下啦！
2013-10-09 14:17:20 補充：
YOU ARE WELCOME。你 D 答案好睇好多。
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