// multiply polynomial by a constant
Poly operator*(const Poly &left, const double k){
int n = left.length();
double x[n];
for (int i = 0; i < n; i++) {
x[i] = left(i)*k;
}
return Poly(n, x);
}
Poly Poly::backwardsIntegrate() const{
Poly p = this->integrate();
double const_term = 0.0;
for (int i = 0; i < p.length() - 1; i++) {
const_term += p(i);
p(i) = -p(i);
}
p += const_term;
return p;
}
