4. Usando la bilinealidad de f : f(x, y) = f  m∑ i=1 xiui, n∑ j=1 yjuj  = m∑ i=1 xi f ui, n∑ j=1 yjvj  = m∑ i=1 xi  n∑ j=1 yj f(ui, vj) ...

4. Usando la bilinealidad de f : f(x, y) = f
 m∑
i=1
xiui,
n∑
j=1
yjuj
 = m∑
i=1
xi f
ui, n∑
j=1
yjvj

=
m∑
i=1
xi
 n∑
j=1
yj f(ui, vj)
 = [x1, x2, . . . , xm]

∑n
j=1 yj f(u1, vj)∑n
j=1 yj f(u2, vj)
...∑n
j=1 yj f(um, vj)

=
[
x1, x2, . . . , xm
]

∑n
j=1 yj a1j∑n
j=1 yj a2j
...∑n
j=1 yj amj

=
[
x1, x2, . . . , xm
]

a11 a12 . . . a1n
a21 a22 . . . a2n
...
...
am1 am2 . . . amn


y1
y2
...
yn
 .