Yazhe 發問時間: 科學數學 · 10 年前

中譯英...help!!!!!(5分)

5(2^x)-9(2^x-1)/3√8^x-4(2^x-4)

其實x--1同x-4係指數黎架,唔係另外減1,减4,我唔識縮細,令佢變指數

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  • 最佳解答

    中譯英~??

    你 expect 咩答案先~

    係咪將「其實x--1同x-4係指數黎架,唔係另外減1,减4,我唔識縮細,令佢變指數」變成英文「In fact, the terms x-1 and x-4 are indice, instead of separate terms x and -1 as well as x and -4. I don't know how to type superscript to make them look like indice.」呀~......

    我斷估都唔係嘅,你應該係想問條數點計至真~ 係咪~??

    首先條式係咁樣寫:5(2^x) - 9 [2^(x-1)] /( 3√8^x) - 4 [2^(x-4)]

    對黃色括號係我加的,因為咁樣會清楚d, 唔好俾其他人誤以為係 { 9 [2^(x-1)] ÷ 3 } × (√8^x) 啦... ...

    條數做法如下:

    5(2^x) - 9 [2^(x-1)] / (3 √8^x) - 4 [2^(x-4)]

    = 5 × 2^[2+(x-2)] - 9 × 2^(x-1) ÷ [ 3 × √(2³)^x ] - 2² × 2^(x-4)

    = 5 × [4 × 2^(x-2)] - 9 × 2^(x-1) ÷ [ 3 × 2^(3x/2) ] - 2^[2+(x-4)]

    = 20 × 2^(x-2) - (9÷3) × 2^[(x-1)-(3x/2)] - × 2^(x-2)

    = (20 - 1) × 2^(x-2) - 3 × 2^ (-1 - x/2)

    = 19 × 2^(x-2) - 3 × 2^ (-1 - x/2)

    = 19 × 2^(x-2) - 3 / [ 2^ (1 + x/2) ]

    參考資料: 自己
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