求不定积分
5个回答
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(10)原式=∫e^x dx/[e^x (1+e^x)]
=∫[1/e^x - 1/(1+e^x)]d(e^x)
=lne^x - ln(1+e^x) + C
=x - ln(1+e^x) +C
(11)原式=∫dx/[cos²x (tanx +2)²]
=∫d(tanx)/(tanx+2)²
=-1/(tanx+2) +C
(12)原式=∫(cscx)^4 dx
=∫(1+cot²x)csc²x dx
=-∫(1+cot²x) d(cotx)
=-cotx - [(cotx)^3]/3 +C
=∫[1/e^x - 1/(1+e^x)]d(e^x)
=lne^x - ln(1+e^x) + C
=x - ln(1+e^x) +C
(11)原式=∫dx/[cos²x (tanx +2)²]
=∫d(tanx)/(tanx+2)²
=-1/(tanx+2) +C
(12)原式=∫(cscx)^4 dx
=∫(1+cot²x)csc²x dx
=-∫(1+cot²x) d(cotx)
=-cotx - [(cotx)^3]/3 +C
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展开全部
(10) ∫1/(1+e^x)dx
=∫ [1 - e^x/(1+e^x))dx
=x-∫1/(1+e^x)d(1+e^x)
=x-ln(1+e^x)+C
(11) ∫dx/(sinx+2cosx)^2
=∫dx/(cosx)^2 * (tanx+2)^2
=∫d(tanx+2)/(tanx+2)^2
=-1/(tanx+2)+C
(12) ∫1/(sinx)^4dx
=∫(cscx)^4dx
=∫csc²x*csc²xdx
=-∫csc²xdcotx
=-∫(cot²x+1)dcotx
=-cot³x/3-cotx+c
=∫ [1 - e^x/(1+e^x))dx
=x-∫1/(1+e^x)d(1+e^x)
=x-ln(1+e^x)+C
(11) ∫dx/(sinx+2cosx)^2
=∫dx/(cosx)^2 * (tanx+2)^2
=∫d(tanx+2)/(tanx+2)^2
=-1/(tanx+2)+C
(12) ∫1/(sinx)^4dx
=∫(cscx)^4dx
=∫csc²x*csc²xdx
=-∫csc²xdcotx
=-∫(cot²x+1)dcotx
=-cot³x/3-cotx+c
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