def binome(n):
    pascal=[1,0]
    k=1
    while k<=n:
        k=k+1
        pascal2=[1]
        for i in range(1,k):
            pascal2.append(pascal[i-1]+pascal[i])
        pascal=pascal2
        pascal.append(0)
    pascal.remove(0)
    return pascal
def developpe(a,b,k):
    S=0
    L=binome(k)
    for i in range(k+1):
        S=S+L[i]*a**(k-i)*b**i
    return S