Functions

•mWBᵈBogqGe functions •mWBᵈBogg%ao
9
In
grade we
only look at
straight line
graphs next year we


look for Linear
at more
types
but now
only graphs .




We need to remember 2 formulas :




Ya Y


]
-

,

Y mxtc
=




[
M =
x, -
× ,




¥am¥nef◦r general formula :



m is your
gradient
C where cuts
is the
graph your
y-axis




{wnww)
axis is which :




Y to the
is
sky




y -9×15




x-axis

, Gradient
changes :




positive gradient negative gradient




Horizontal
graphs
:




y =


eg
.




5
< >
y=5
°
< >
y
• :O
-2
>
<
y = -2




vertical
graphs
:




✗ =




✗= -
l x :O
ax 7
=
a a



7
-
,




r
v v

, How to find the formula :


i




42 -

Yi *
NB : the smaller the
gradient the

Mx + C M =

y
flatter
= the
graph ,
the
bigger
✗z -
x,
the
gradient the steeper the


graph

steps :

example 1 :


1 Choose
any 2 pts .
label them pt . I É pt 2
.




/
°
X, Y ,


" " " " [ " " " " " "




Xz 42
( -2 ; 1) -
→ pt . 2


2 Now lets find
◦

C- 2 ;
the
gradient
-
1)
yz -
Yi
M =
✗z -
Xi

(2)




n÷÷÷÷g:
C- 1) -




É÷÷÷÷÷
=
7
( -

2) -
( l )




I ;÷:÷ˢn
.
L
=
3
-




we
-

3
are
happy with a
positive

=
,
and label them cod y 't -




3 Now find ordinate
we have to C
by subbing in
any co -

.




lets use pt
§
.




Y = Mx + c m = , ( 1 ; 2)
SO ✗ =\
(2) =
(1) + c y=z

2 =
I + C




2 I
-


= C




C = I




i. 1×+1
y
=