for 00
= 0 for x=0
= -2^x/(4^x+1) for x0
f'(x) = -2^x(ln 4) 4^x/ (4^x+1)^2 + (ln2)2^x/ (4^x+1)
= [-2^x(ln 4) 4^x + (4^x+1).2^x.(ln2)]/(4^x+1)
= 2^x ln2(1-2^x)/(4^x+1) < 0
f is decreasin on (0,1)
for x
for 00
= 0 for x=0
= -2^x/(4^x+1) for x0
f'(x) = -2^x(ln 4) 4^x/ (4^x+1)^2 + (ln2)2^x/ (4^x+1)
= [-2^x(ln 4) 4^x + (4^x+1).2^x.(ln2)]/(4^x+1)
= 2^x ln2(1-2^x)/(4^x+1) < 0
f is decreasin on (0,1)
for x