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Evaluate:`int1/((x+1)sqrt(x^2+x+1))dx` |
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Answer» Correct Answer - `-log|(1)/(x+1)-(1)/(2)+(sqrt(x^(2)+x+1))/(x+1)|+C` `I=int(1)/((x+1)sqrt(x^(2)+x+1))dx` ` "Let " x+1=(1)/(t) " or " dx=-(1)/(t^(2))dt ` `:. I=int(1)/((1)/(t)sqrt(((1)/(t)-1)^(2)+((1)/(t)-1)+1))(-(1)/(t^(2)))dt` `=-int(dt)/(sqrt((1-t)^(2)+(t-t^(2))+t^(2)))` `=-int(dt)/(sqrt(t^(2)-t+1))` ` =-int(dt)/(sqrt((t-(1)/(2))^(2)+(3)/(4)))` `=-log|(t-(1)/(2))+sqrt(t^(2)-t+1)|+C` `=-log|(1)/(x+1)-(1)/(2)+(sqrt(x^(2)+x+1))/(x+1)|+C` |
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