第5小题,要过程,急求,谢谢。

求下列不定积分
2025-05-22 08:28:27
推荐回答(1个)
回答(1):

解答过程如下:
∫[-1,3][1/(x²+4x+5)]dx
=∫[-1,3]{1/[(x+2)²+1]}dx
=arctan(x+2)|[-1,3]
=arctan3-arctan(-1)
=3-(-π/4)
=3+π/4

我写过一道类似的,但是上限不同的,也给你附上:
∫[-1,-3][1/(x²+4x+5)]dx
=∫[-1,-3]{1/[(x+2)²+1]}dx
=arctan(x+2)|[-1,-3]
=arctan(1)-arctan(-1)
=π/4-(-π/4)
=π/2