Miscellaneous questions on functions (preliminary) (1 Viewer)

[Starrzz]

I am quite confused about these questions, and don't know how to go about doing them. Help would be appreciated

1.


2.


3.

 

[SeCKSiiMiNh]

I am quite confused about these questions, and don't know how to go about doing them. Help would be appreciated

1.

1. f(x)= 5x - x^2
f(x + h) = 5(x+h) - (x+h)^2

therefore, f(x +h) - f(x) = [5(x+h) - (x+h)^2] - [5x - x^2]
= 5x + 5h - (x^2 + 2xh + h^2) - 5x + x^2
= 5h - x^2 - 2xh - h^2 + x^2
= -h^2 - 2xh + 5h

 

[adomad]

all you need to do for the first one is sub in (x+h) for every x so if f(x)=5x-x^2. f(x+h)= 5(x+h)-(x+h)^2. when you minus the f(x) you just do normal algebra

and the other questions are similar

 

[SeCKSiiMiNh]

I am quite confused about these questions, and don't know how to go about doing them. Help would be appreciated

2.

f(x) = x^2 + 4x -5
f(x+h) = (x + h)^2 + 4(x+h) - 5

therefore, f(x+h) - f(x) =

(x^2 + 2xh + h^2) + 4x + 4h - 5 - x^2 - 4x +5

2xh + h^2 +4h

on the 2nd part, simply divide everything in part 1 by h which equals : 2x + h + 4

 

[demikid]

These questions seem soooo familiar - I did exactly the same questions for maths just a week ago..

Any chance we in the same class? haha

 

[Starrzz]

These questions seem soooo familiar - I did exactly the same questions for maths just a week ago..

Any chance we in the same class? haha

Haha, doubt it, I would know if we were in the same class =P

I understand now how to do these types of questions, if I have more questions I will be back. Thank you for all the help.