評量5.36

  1. 0.4772 + 0.4987 = 0.9759
  2. + c
  3. = = = ln2 + 3/2
  4. = = 16/3
  5. = =
  6. = =
  7. = = ln|y+4| + c
  8. = = (1/5)x5 + 2x3 + 9x + c
  9. = = x + ln|x| + c
  10. = (1/2)ln|2x-1| + c
  11. = =
  12. 則: 則: c3 - c2 - 6c + 6 = 0
    c = 1 or sqrt(6) or - sqrt(6)
    但 c = 1 or - sqrt(6)不合 , ∴ c = sqrt(6)
  13. = =

RED  :sinx
BLUE:x(x-π)

評量5.37

註:因為積分步驟因人而異,所以答案不是唯一,故此答案作為參考用。
將所算出之答案微分後,等於原積分之函數即可。

  1. ∫(lnx/x)dx = ∫(lnx)d(lnx) = (1/2)(ln|x|)2 + c
  2. ∫(esinxcosx)dx = ∫(esinx)d(sinx) = esinx + c
  3. ∫(cos2xsin5x)dx = -∫(cos2xsin4x)d(cosx) =
    -∫[cos2x(1-cos2x)2]d(cosx) = ∫[-cos2x + 2cos4x - cos6x]d(cosx) =
    -(1/3)cos3x + (2/5)cos5x - (1/7)cos7x + c
  4. ∫[(x+7)(3-2x)(1/3)]dx = (-1/2)∫[y(1/3)(17/2 - (1/2)y)]dy (令y = 3-2x)=
    (3/28)(3-2x)(7/3) - (51/16)(3-2x)(4/3) + c
  5. ∫[3x/(x2 - 2x - 8)]dx + ∫(3/2)d(ln|x2 - 2x - 8| + ∫[3/(x+2)(x-4)]dx =
    ∫[3x/(x2 - 2x - 8)]dx + ∫[(-1/2)/(x+2)]dx + ∫[(1/2)/(x-4)]dx =
    (3/2)ln|x2 - 2x - 8| - (1/2)ln|x+2| + (1/2)ln|x-4| + c
    另解:2ln|x+4| + ln|x-2| + c
  6. ∫[1/(x2 - 6x + 12)]dx = ∫{1/[(x-3)2 + 3]}dx =
    ∫[√3/(3y2 + 3)]dy (令x = 3 + √3y)= (√3/3)tan-1[(x-3)/√3] + c
  7. = (令 y = lnx => x = ey)= =
    = = 3(e2 - e)
  8. = = 1
  9. (1/7)(57 - 37)
  10. 如圖設a,b分別為下圖中的半長軸和半短軸長,則橢圓面積 = 4 X 藍色部分面積
    由橢圓一般式 : x2/a2 + y2/b2 = 1 知 :
    y = b(1 - x2/a2)(1/2)
    則藍色部分面積 = (令x = asinT)= =

    所以橢圓面積 =