①∫(1-x)/√9-4x² dx
问题描述:
①∫(1-x)/√9-4x² dx
②∫√x²-9/x dx
③∫dx/√1+e^x
答
①(1-x)/(9-4x^2)^(1\2)=1\2(9\4-x^2)^(1\2)
-4x/4(9-4x^2)^(1\2)
∴∫(1-x)/√9-4x² dx
=(1/2)*arcsin(2x/3)+(1/4)*(9-4x^2)^(1/2)+C
②设x=3sect 0