a = 0.2 (slider from 0 to 1, step 0.02)
b = 1.8 (slider from 1 to 5, step 0.05)
f(x) = log(x) / log(b)
g(x) = log(x) / log(a)
texto1: "f_1(x)=\log_a x=\log_{" + (LaTeX[a]) + "}x"
texto2: "f_2(x)=\log_b x=\log_{" + (LaTeX[b]) + "} x"