#include <bits/stdc++.h>
using namespace std;
int n, m;
double b[100005];
struct node {
  double he, cheng;
} a[100005 * 4];
node merge(node a, node b) {
  node c;
  c.cheng = a.cheng * b.cheng;
  c.he = a.he + a.cheng * (b.he - 1);
  return c;
}
void build(int x, int l, int r) {
  if (l == r) {
    a[x].he = 1 + b[l];
    a[x].cheng = b[l];
    return;
  }
  int mid = (l + r) / 2;
  build(x * 2, l, mid);
  build(x * 2 + 1, mid + 1, r);
  a[x] = merge(a[x * 2], a[x * 2 + 1]);
}
void modify(int x, int l, int r, int wh, double val) {
  if (l == r) {
    a[x].cheng = val;
    a[x].he = 1 + val;
    return;
  }
  int mid = (l + r) / 2;
  if (mid >= wh)
    modify(x * 2, l, mid, wh, val);
  else
    modify(x * 2 + 1, mid + 1, r, wh, val);
  a[x] = merge(a[x * 2], a[x * 2 + 1]);
}
node query(int x, int l, int r, int tx, int ty) {
  if (l >= tx && r <= ty) return a[x];
  int mid = (l + r) / 2;
  if (mid >= tx && mid < ty)
    return merge(query(x * 2, l, mid, tx, ty),
                 query(x * 2 + 1, mid + 1, r, tx, ty));
  if (mid >= tx)
    return query(x * 2, l, mid, tx, ty);
  else
    return query(x * 2 + 1, mid + 1, r, tx, ty);
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) {
    double x, y;
    scanf("%lf%lf", &x, &y);
    double t = x / y;
    b[i] = (1 - t) / t;
  }
  build(1, 1, n);
  while (m--) {
    int type;
    scanf("%d", &type);
    if (type == 1) {
      int wh;
      scanf("%d", &wh);
      double x, y;
      scanf("%lf%lf", &x, &y);
      double t = x / y;
      t = (1 - t) / t;
      modify(1, 1, n, wh, t);
    } else {
      int x, y;
      scanf("%d%d", &x, &y);
      printf("%.10lf\n", 1.0 / query(1, 1, n, x, y).he);
    }
  }
  return 0;
}
