Question

If dy/dx=4y and y=4 when x=0, then y=. A) 4e^4x. B) e^4x. C) 3+e^4x. D) 4+e^4x. e) 2x^2+4

Answer 1

Hello,

dy/dx=4==>dy/y=4dx==>ln(y)=4x+C
==>y=k*e^(4x)
if x=0 y=4==>4=k*e^(4*0)==>k=4

==>y=4*e^(4x)

Answer A (with parenthesis!!!)