diff --git a/aula2.py b/aula2.py
index 9dcf700..17d1b4b 100644
--- a/aula2.py
+++ b/aula2.py
@@ -1,34 +1,45 @@
-#Exercicio 4.1
-impar = None
+# Exercicio 4.1
+impar = lambda x: x % 2 != 0
 
-#Exercicio 4.2
-positivo = None
+# Exercicio 4.2
+positivo = lambda x: x > 0
 
-#Exercicio 4.3
-comparar_modulo = None
+# Exercicio 4.3
+comparar_modulo = lambda x, y: abs(x) < abs(y)
 
-#Exercicio 4.4
-cart2pol = None
+# Exercicio 4.4
+cart2pol = lambda x, y: ((x**2 + y**2)**0.5, sum([((-1)**n * (y/x)**(2*n + 1)) / (2*n + 1) for n in range(100000)]) if x != 0 else 3.141592653589793/2)
 
-#Exercicio 4.5
-ex5 = None
+# Exercicio 4.5
+ex5 = lambda f, g, h: lambda x, y, z: h(f(x, y), g(y, z))
 
-#Exercicio 4.6
+
+# Exercicio 4.6
 def quantificador_universal(lista, f):
-    pass
+    return [x for x in lista if not f(x)] == []
 
-#Exercicio 4.8
+
+# Exercicio 4.7
+def quantificador_existencial(lista, f):
+    return [x for x in lista if f(x)] != []
+
+
+# Exercicio 4.8
 def subconjunto(lista1, lista2):
-    pass
+    return [x for x in lista1 if x in lista2] == lista1
 
-#Exercicio 4.9
+
+# Exercicio 4.9
 def menor_ordem(lista, f):
-    pass
+    return [x for _ in range(len(lista)) for x in lista if all(f(x, y) for y in lista if x != y)][0]
 
-#Exercicio 4.10
+
+# Exercicio 4.10
 def menor_e_resto_ordem(lista, f):
-    pass
+    m = menor_ordem(lista, f)
+    return m, [x for x in lista if x != m]
 
-#Exercicio 5.2
+
+# Exercicio 5.2
 def ordenar_seleccao(lista, ordem):
     pass