Touba M. answered 11/10/21
B.S. in Pure Math with 20+ Years Teaching/Tutoring Experience
Hi,
y = xe^-bx
is your question y = x e-bx ???
if yes, take a derivative of function
y' = 1 * e-bx + -be-bx * x ( follow product rule)
y' = e-bx ( 1 -bx )
y' = 0 -----> e-bx ( 1 -bx ) = 0 you see only inside of perenties must be zero
1 -bx = 0 ------> x = 1/b then replace to the given function and find the y of critical point
y = x e-bx = 1/b ( e-b(1/b)) = 1/b * e-1 = 1/be critical point is ( 1/b , 1/be)
I hope it is useful,
Minoo