Question

what am i doing wrong here?

f(x)= 2x^2+1 find f(x+1)-[f(x)+1]

Answer 1

Do you know how to find \(f(x+h)\)

Answer 2

\[2(x+1)^2+1\]

Answer 3

Now expand.

Answer 4

\[2(x^2+2x+1)+1\]

Answer 5

\[2x^2+4x+4\]

Answer 6

\(+3\)

Answer 7

2 doesn't distribute to the 1 on the outside.

Answer 8

oh

Answer 9

\[(2x^2+1)+1\]

Answer 10

\[2x^2+2\]

Answer 11

Okay now subtract them.

Answer 12

\[(2x^2-3x+4)-(2x^2+2)\]

Answer 13

\[3x+2\]

Answer 14

Where did that -3 and +4 come from?

Answer 15

the oh it should be 3

Answer 16

\[3x+1\]

Answer 17

It should be \(4x\)

Answer 18

ok

Answer 19

\[4x+1\]

Answer 20

That looks right.

Answer 21

http://www.wolframalpha.com/input/?i=2%28x%2B1%29%5E2%2B1++-+%282x%5E2%2B1%2B1%29

Answer 22

ok thanks