10^(2.6025) = 10^2*10^0.60206*10^0.00044102.6025=102⋅100.60206⋅100.00044
~=100*10^(2log_10(2))*10^0.00044≅100⋅102log10(2)⋅100.00044
=100*2^2*10^0.00044=100⋅22⋅100.00044
=400*10^0.00044=400⋅100.00044
Now
1.001^1000 = (1+0.001)^10001.0011000=(1+0.001)1000
=1+((1000),(1))0.001+((1000),(2))0.001^2+...
=1+1+0.4995+0.166167+0.04141712475+...
somewhere between 2.7 and 3
log_10(3) ~= 0.4771 (one of those useful numbers to memorise)
log_10(2.7) = log_10(27/10) = log_10(3^3/10) = 3log_10(3)-1
~= 0.4313
So 0.4313 < 1000 log_10(1.001) < 0.4771
0.0004313 < log_10(1.001) < 0.0004771
So 1.001 is a fairly good approximation for 10^0.00044