Respuesta :

A = ∫₀a ex dx
B = ∫₀b ex dx
B = 4A
4∫₀a ex dx = ∫₀b ex dx
4∫(ea -e⁰) = eb- e⁰
4ea - 4 = eb⁻¹
eb = 4ea - 3
b = In(4ea - 3)