Prove that if (c, f(c)) is a point of inflection of the graph of f and f'' exists in an open interval that contains c, then f''(c)=0 Hint: Apply the First Derivative Test and Fermat's Theorem to the function g=f'

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

i can't see the picture : /