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∫01dxx2+x+1\int_0^1 \frac{dx}{x^2 + x + 1}

Solution

✅ Correct Option: 1

Complete the square: x2+x+1=(x+1/2)2+3/4x^2+x+1 = (x+1/2)^2 + 3/4. Then ∫01dx(x+1/2)2+(3/2)2=23tan⁡−1(2x+13)∣01=23[tan⁡−13−tan⁡−1(1/3)]=23(π3−π6)=π33\int_0^1 \frac{dx}{(x+1/2)^2 + (\sqrt{3}/2)^2} = \frac{2}{\sqrt{3}} \tan^{-1}\left(\frac{2x+1}{\sqrt{3}}\right)\Big|_0^1 = \frac{2}{\sqrt{3}}[\tan^{-1}\sqrt{3} - \tan^{-1}(1/\sqrt{3})] = \frac{2}{\sqrt{3}}(\frac{\pi}{3} - \frac{\pi}{6}) = \frac{\pi}{3\sqrt{3}}.

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