Fie f:R->R, f(x) = [tex] \left \{ {{\frac{1}{x^{2}+1}},x\leq0 \atop {-2x+1},x\ \textgreater \ 0} \right. [/tex] . Determinati ecuatia tangentei [tex] G_{f} [/tex] in punctul A(-1;[tex] \frac{1}{2} [/tex]}