求解微积分:∫1⼀(x^2+9)dx 要过程!!

2024-11-06 18:25:03
推荐回答(4个)
回答1:

∫ 1/(x^2+9) dx
=(1/9)*∫ 1/((x/3)^2+1) dx
=(3/9)*∫ 1/((x/3)^2+1) d(x/3)
=(1/3)*arctan(x/3)+C
有不懂欢迎追问

回答2:

你将1/(x^2+9)提一个1/9,(1/9)*(1/(x/3)^2+1),又arttanx=1/(x^2+1)
所以原式=arttan(x/3)/9+C(C为常数)

回答3:

∫1/(x^2+9)dx

=1/9∫1/(x²/9+1)dx
=1/27∫1/[(x/3)²+1[ d(x/3)
=1/27*arctan(x/3)+C

回答4:

令x=3t
dx=3dt
∫1/(x^2+9)dx
=∫3dt/(9t^2+9)
=(1/3)∫dt/(t^2+1)
=(1/3)arctan t+C
=(1/3)arctan (x/3)+C