문제 1선택형12=3\frac{1}{2=3}???∫0∞2x+1dx\int_0^{\infty}\!2x+1\,dx∫0∞2x+1dx\int_0^{\infty}\!2x+1\,dx∫0∞2x+1dx\int_0^{\infty}\!2x+1\,dx∫0∞2x+1dx\int_0^{\infty}\!2x+1\,dx∫0∞2x+1dx\int_0^{\infty}\!2x+1\,dx∫0∞2x+1dx\int_0^{\infty}\!2x+1\,dx∫0∞2x+1dx\int_0^{\infty}\!2x+1\,dx22+12^2+1
