Given a base 1, C2 in the plane. define a linear mapping / of the plane on itself through the conditions F(e1) = 2 . e1 + e2 and F(e2) = e2. Then define a sequence U1, U2, U3, ... of vectors in the plane by putting U1 = 3 . e1 + 1 . e2 and Un+1 = F( Un) . Enter a formula for Un as a function of n. Svar: Un = ( je1 + ( Je2