Choose the correct answer in Exercises 21 and 22 21 The anti derivative of 
1
x
x


+




 equals
(A)
1
1
3
2
1
2
C
3
x
x
+
+
(B)
2
2
23
1
C
3
2
x
x
+
+
(C)
3
1
2
2
2
2
C
3
x
x
+
+
(D)
3
1
2
2
3
1
C
2
2
x
x
+
+
22 If 
3
34
( )
4
d f x
x
dx
x
=
−
 such that f (2) = 0