求不定积分:1/(x+sqrt(x^2-x+1))

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求不定积分:1/(x+sqrt(x^2-x+1))
求不定积分:1/(x+sqrt(x^2-x+1))

求不定积分:1/(x+sqrt(x^2-x+1))
1/(x+sqrt(x^2-x+1))=[sqrt(x^2-x+1)-x]\(1-x)
sqrt(x^2-x+1)\(1-x)dx=-sqrt(t^2-t+1)\tdt t=1-x
-sqrt(t^2-t+1)\t=1\2sqrt(t^2-t+1)-(t-1\2)\sqrt(t^2-t+1)
-1\tsqrt(t^2-t+1)
u=1\t -1\tsqrt(t^2-t+1)dt=sgnu\sqrt(u^2-u+1)du
原式=∫1\2sqrt(t^2-t+1)-(t-1\2)\sqrt(t^2-t+1)dt+∫sgnu\sqrt(u^2-u+1)du
+x+In|x-1|+C
=(1\2)In[t-1\2+sqrt(t^2-t+1)]-sqrt(t^2-t+1)+In|1\t-1\2+sqrt(t^2-t+1)\t|
+x+In|x-1|+C
=(1\2)In[sqrt(x^2-x+1)-x+1\2]+In[sqrt(x^2-x+1)+(x+1)\2]+x-sqrt(x^2-x+1)
+C