#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
pair<double, double> A[maxn << 2];
void PushUp(int rt) {
  A[rt].first = A[rt << 1].first * A[rt << 1 | 1].first;
  A[rt].second = A[rt << 1].second + A[rt << 1 | 1].second * A[rt << 1].first;
}
void build(int l, int r, int rt) {
  if (l == r) {
    A[rt].first = 1.0;
    A[rt].second = 0;
    return;
  }
  int m = (l + r) >> 1;
  build(l, m, rt << 1);
  build(m + 1, r, rt << 1 | 1);
}
void update(int p, pair<double, double> tmp, int l, int r, int rt) {
  if (l == r) {
    A[rt] = tmp;
    return;
  }
  int m = (l + r) >> 1;
  if (p <= m)
    update(p, tmp, l, m, rt << 1);
  else
    update(p, tmp, m + 1, r, rt << 1 | 1);
  PushUp(rt);
}
pair<double, double> query(int L, int R, int l, int r, int rt) {
  if (L <= l && r <= R) {
    return A[rt];
  }
  int m = (l + r) >> 1;
  pair<double, double> AA = {1.0, 0}, BB = {1.0, 0}, CC;
  if (L <= m) AA = query(L, R, l, m, rt << 1);
  if (R > m) BB = query(L, R, m + 1, r, rt << 1 | 1);
  CC.first = AA.first * BB.first;
  CC.second = AA.second + BB.second * AA.first;
  return CC;
}
int main() {
  int n, q;
  scanf("%d %d", &n, &q);
  build(1, n, 1);
  for (int i = 1; i <= n; i++) {
    double a, b;
    scanf("%lf %lf", &a, &b);
    double p = a / b;
    double u = (1 - p) / p;
    update(i, make_pair(u, u), 1, n, 1);
  }
  for (int i = 1; i <= q; i++) {
    int op, a, b, c;
    scanf("%d", &op);
    if (op == 1) {
      scanf("%d %d %d", &a, &b, &c);
      double p = 1.0 * b / (1.0 * c);
      double u = (1 - p) / p;
      pair<double, double> D = make_pair(u, u);
      update(a, D, 1, n, 1);
    } else {
      scanf("%d %d", &a, &b);
      double p = query(a, b, 1, n, 1).second;
      double ans = 1.0 / (1.0 + p);
      if (ans >= 0)
        printf("%.10f\n", 1.0 / (1.0 + p));
      else
        printf("0\n");
    }
  }
}
