用不定积分第二换元法解道题 ∫ 1/(x+√1-x²)dx

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用不定积分第二换元法解道题 ∫ 1/(x+√1-x²)dx

用不定积分第二换元法解道题 ∫ 1/(x+√1-x²)dx
用不定积分第二换元法解道题 ∫ 1/(x+√1-x²)dx

用不定积分第二换元法解道题 ∫ 1/(x+√1-x²)dx

令x=sinu,√(1-x²)=cosu,dx=cosudu
∫1/(x+√(1-x²))dx
=∫1/(sinu+cosu)*(cosu)du
=∫cosu/(sinu+cosu)du
=1/2∫(cosu+sinu+cosu-sinu)/(sinu+cosu)du
=1/2∫(cosu+sinu)/(sinu+cosu)du+1/2∫(cosu-sinu)/(sinu+cosu)du
=1/2∫1du+1/2∫1/(sinu+cosu)d(sinu+cosu)
=(1/2)u+(1/2)ln|sinu+cosu|+C
=(1/2)arcsinx+(1/2)ln|x+√(1-x²)|+C