Derivative of Log base 4 [( x^2+1)]=y the long way?

Derivative of Log base 4 [( x^2+1)]=y the long way? Calc BC
if you change to 4^y=x^2+1 and then hy cant you NOT have the capatilized part? yln(4)=LN(X^2)+LN(1) ...why is that step not correct?

Jeremy2014-10-23T17:17:56Z

the logarithm function does not distribute over the addition like that,
log(a + b)
does not equal
log(a) + log(b)

we have:
4^y = x^2 + 1
ln(4^y) = ln(x^2 + 1)
y*ln(4) = ln(x^2 + 1)

ln(4) dy = 2x/(x^2 + 1) dx

dy/dx = 2x/(x^2 + 1) * (1/ln(4))
dy/dx = 2x/(x^2 + 1) * (1/ln(2^2))
dy/dx = 2x/(x^2 + 1) * (1/(2ln(2)))
dy/dx = x/(x^2 + 1) * (1/ln(2))
dy/dx = x/[ln(2)*(x^2 + 1)]

or, if u prefer:
dy/dx = x/ln(2^(x^2 + 1))