from decimal import getcontext,Decimal
import sys

input=sys.stdin.readline
write=sys.stdout.write

getcontext().prec=30

T=int(input())
X=[0]*T

for case in range(T):
    p,K=map(Decimal,input().split())

    if p>0:
        X[case]=(1-pow(1-p,K))/p
    else:
        X[case]=K

write("\n".join(map(str,X)))