Posted by andi telaumbanua on Feb 17, 2018 in
Matematika |
Hitunglah integral berikut:
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∫ (2x+10)dx
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∫ √(8+5x) dx
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∫ dx /(3x+1)^2
Jawab:
1.∫ (2x+10) dx = 2/(1+1) x^(1+1)+ 10x+C = x^2+ 10x+C
2. Misalkan : u = 8 + 5x
Maka: du/dx=5 Sehingga: dx = 1/5 du
∫ √(8+5x) dx = ∫ (u)^(1/2) 1/5 du = 1/5 ∫ (u)^(1/2) du = (1/5) 1/(1/2+ 1) u^(1/2+1)+ C = (1/5) 2/3 u^(3/2)+ C = 2/15 (8+5x)^(3/2)+ C= 2/15 (8+5x) √(8+5x)+C
3. Misalkan: u = 3x+1
Maka: du/dx=3 Sehingga : dx = du/3
∫ dx /(3x+1)^2 = ∫ (du/3) /(u)^2 = 1/3 ∫ du /(u)^2 = 1/3 1/(-2+1) (u)^(-2+1) +C = 1 /(-3) u^(-1) + C = 1 / (-3) (3x+1)^(-1) + C = (-1) /(9x+3) + C
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