integral dari : (a) ∫x e^( x^2 ) dx (b)∫ dx/(x lnx ) (c) ∫ (e^x dx)/(1+2e^x )
Posted by andi telaumbanua on Feb 17, 2018 in Matematika |
Tentukanlah Integral dari :
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∫x e^( x^2 ) dx
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∫ dx/(x lnx )
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∫ (e^x dx)/(1+2e^x )
Jawab:
1. Misalkan: u = x^2
Maka: du/dx = 2x
Sehingga : dx = du/2x
∫ x e^( x^2 ) dx = ∫ x e^u du/2x = 1/2 ∫ e^u du = 1/2 e^u + C = 1/2 e^(x^2 ) + C
2. Misalkan: u = ln x
Maka: du/dx = 1/x
Sehingga : dx = x du
∫ dx /(x lnx ) = ∫ (x du) /(x u) = ∫ ( du) / u = ln|u| + C = ln |lnx | + C = ln ln x + C
3. Misalkan: u = 1 + 2e^x
Maka: du/dx = 2e^x
Sehingga : dx = du /2e^x
∫ (e^x dx) /(1+2e^x ) = ∫ (e^x ) /u (du /2e^x) = 1/2 ∫ du /u = 1/2 ln|u| + C = 1/2 ln|1 + 2e^x| + C