Solución
Apartado a
Apartado b
lim
h
→
1
−
2
h
h
≠
lim
h
→
1
+
2
x
+
h
−
2
x
h
\mathop {\lim }\limits_{h \to {1^ - }} {{2h} \over h} \ne \mathop {\lim }\limits_{h \to {1^ + }} {{{2 \over {x + h}} - {2 \over x}} \over h}
h
→
1
−
lim
h
2
h
=
h
→
1
+
lim
h
x
+
h
2
−
x
2
