Question

which is true statement about functions?
A. if f and g are functnions then (g o f)(x)=(f o g)(x)
B. if a and b are matrices, then ab can always be computed.
C. if f and g are functions then (f+g)(-2)=(g+f)(-2)
D. if f is a function then f(2+h)=f(2)+f(h)

Answer 1

which one do you think it is?

Answer 2

c

Answer 3

nvm d

Answer 4

lol flutter, it was c... :C

Answer 5

now, why didn't d work though o.o

Answer 6

Example of why D doesn't work

f(x) = x^2

f(2+h) = (2+h)^2

f(2+h) = 4 + 2h + h^2

------------------------

f(2) = 2^2

f(2) = 4

------------------------

f(h) = h^2

===========================

So

f(2+h) = f(2)+f(h)

becomes

4 + 2h + h^2 = 4 + h^2

which is only true when h = 0

Answer 7

hmm, I forgot about the 2h... I'm not sure where the 2h came from though. did you distribute ^2 and then aftewards add 2+h

Answer 8

(2+h)^2 = (2+h)(2+h)

(2+h)^2 = 2(2+h) + h(2+h)

(2+h)^2 = 2*2+2h + 2h+h*h

(2+h)^2 = 4+2h + 2h+h^2

(2+h)^2 = 4+4h+h^2

hmm sry about that, made a typo and it should be (2+h)^2 = 4+4h+h^2 and not 4+2h+h^2, my bad

but it still holds true why D doesn't work