f(x)
=
2f(2)
-
x？
+
8x
-
eight
f( 1)
=
2f( 1)
-
1
+
eight
-
eight
f( 1)
=
1
df(x)/dx
=
-2df(2-x)/dx
-
2x
+
eight
df( 1)/dx
=
-2df( 1)/dx
-
2
+
eight
df( 1)/dx
=
2
Tangent equation: y
=
2x
+
c
Substitute x= 1, f( 1)= 1,
Get:
1
=
2
+
c，c
=
- 1
Therefore, the tangent equation at (1, f( 1)) is y.
=
2x
-
1