\[ \left (x^2+1\right ) y'(x)^2-2 x y(x) y'(x)+y(x)^2-1=0 \] ✓ Mathematica : cpu = 0.0385488 (sec), leaf count = 45
DSolve[-1 + y[x]^2 - 2*x*y[x]*Derivative[1][y][x] + (1 + x^2)*Derivative[1][y][x]^2 == 0,y[x],x]
\[\left \{\left \{y(x)\to c_1 x-\sqrt {1-c_1{}^2}\right \},\left \{y(x)\to c_1 x+\sqrt {1-c_1{}^2}\right \}\right \}\] ✓ Maple : cpu = 0.052 (sec), leaf count = 57
dsolve((x^2+1)*diff(y(x),x)^2-2*x*y(x)*diff(y(x),x)+y(x)^2-1 = 0,y(x))
\[y \left (x \right ) = \sqrt {x^{2}+1}\]