tan−1x(x+1)+sin−1x2+x+1=2π⇒tan−1x2+x+sin−1x2+x+1=2πThis equation holds true, if
x2+x≥0and0≤x2+x+1≤1Now,
x2+x≥0and0≤x2+x+1≤1⇒x2+x≥0andx2+x+1≤1[∵x2+x+1>0for all x]<br/><br/>⇒ x^{2} +
x≥0and x^{2} +
x≤0⇒x2+x=0⇒x=0,−1.<br/><br/>Clearly,thesetwovaluessatisfythegivenequation.Hence, x = - 1, 0
arethesolutionsofthegivenequation.