6. Differentiating
Logarithms
y log f x
dy f x
dx f x
e.g. (i) y log3 x 5
y log a f x
dy
f x
dx log a f x
7. Differentiating
Logarithms
y log f x
dy f x
dx f x
e.g. (i) y log3 x 5
dy
3
dx 3 x 5
y log a f x
dy
f x
dx log a f x
8. Differentiating
Logarithms
y log f x
dy f x
dx f x
e.g. (i) y log3 x 5
dy
3
dx 3 x 5
y log a f x
dy
f x
dx log a f x
ii y log x 3
9. Differentiating
Logarithms
y log f x
dy f x
dx f x
e.g. (i) y log3 x 5
dy
3
dx 3 x 5
y log a f x
dy
f x
dx log a f x
ii y log x 3
dy 3 x 2
3
dx x
10. Differentiating
Logarithms
y log f x
dy f x
dx f x
e.g. (i) y log3 x 5
dy
3
dx 3 x 5
y log a f x
dy
f x
dx log a f x
ii y log x 3
dy 3 x 2
3
dx x
3
x
11. Differentiating
Logarithms
y log f x
dy f x
dx f x
e.g. (i) y log3 x 5
dy
3
dx 3 x 5
y log a f x
dy
f x
dx log a f x
ii y log x 3 OR
2
dy 3 x
3
dx x
3
x
y log x 3
12. Differentiating
Logarithms
y log f x
dy f x
dx f x
e.g. (i) y log3 x 5
dy
3
dx 3 x 5
y log a f x
dy
f x
dx log a f x
ii y log x 3 OR
2
dy 3 x
3
dx x
3
x
y log x 3
y 3 log x
13. Differentiating
Logarithms
y log f x
dy f x
dx f x
e.g. (i) y log3 x 5
dy
3
dx 3 x 5
y log a f x
dy
f x
dx log a f x
ii y log x 3 OR
2
dy 3 x
3
dx x
3
x
y log x 3
y 3 log x
dy 3
dx x
16. (iii) y loglog x
1
dy
x
dx log x
1
x log x
17. (iii) y loglog x
1
dy
x
dx log x
1
x log x
iv y log x 3 x 2
18. (iii) y loglog x
1
dy
x
dx log x
1
x log x
iv y log x 3 x 2
dy x 31 x 2 1
x 3 x 2
dx
19. (iii) y loglog x
1
dy
x
dx log x
1
x log x
iv y log x 3 x 2
dy x 31 x 2 1
x 3 x 2
dx
2x 5
x 3 x 2
20. (iii) y loglog x
1
dy
x
dx log x
1
x log x
iv y log x 3 x 2
dy x 31 x 2 1
x 3 x 2
dx
2x 5
x 3 x 2
OR
y log x 3 log x 2
21. (iii) y loglog x
1
dy
x
dx log x
1
x log x
iv y log x 3 x 2
dy x 31 x 2 1
x 3 x 2
dx
2x 5
x 3 x 2
OR
y log x 3 log x 2
dy
1
1
dx x 3 x 2
22. (iii) y loglog x
1
dy
x
dx log x
1
x log x
iv y log x 3 x 2
dy x 31 x 2 1
x 3 x 2
dx
2x 5
x 3 x 2
OR
y log x 3 log x 2
dy
1
1
dx x 3 x 2
x 2 x 3
x 3 x 2
23. (iii) y loglog x
1
dy
x
dx log x
1
x log x
iv y log x 3 x 2
dy x 31 x 2 1
x 3 x 2
dx
2x 5
x 3 x 2
OR
y log x 3 log x 2
dy
1
1
dx x 3 x 2
x 2 x 3
x 3 x 2
2x 5
x 3 x 2
25. x 5
v y log
x 2
x 21 x 51
dy
x 22
x5
dx
x2
26. x 5
v y log
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
27. x 5
v y log
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
28. x 5
v y log
OR
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
y log x 5 log x 2
29. x 5
v y log
OR
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
y log x 5 log x 2
dy
1
1
dx x 5 x 2
30. x 5
v y log
OR
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
y log x 5 log x 2
dy
1
1
dx x 5 x 2
x 2 x 5
x 5 x 2
31. x 5
v y log
OR
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
y log x 5 log x 2
dy
1
1
dx x 5 x 2
x 2 x 5
x 5 x 2
3
x 2 x 5
32. x 5
v y log
OR
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
vi y log10 6 x
y log x 5 log x 2
dy
1
1
dx x 5 x 2
x 2 x 5
x 5 x 2
3
x 2 x 5
33. x 5
v y log
OR
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
vi y log10 6 x
dy
6
dx log 10 6 x
y log x 5 log x 2
dy
1
1
dx x 5 x 2
x 2 x 5
x 5 x 2
3
x 2 x 5
34. x 5
v y log
OR
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
vi y log10 6 x
dy
6
dx log 10 6 x
1
x log 10
y log x 5 log x 2
dy
1
1
dx x 5 x 2
x 2 x 5
x 5 x 2
3
x 2 x 5
35. x 5
v y log
OR
x 2
x 21 x 51
dy
x 22
x5
dx
x2
3
x 2
x 22 x 5
3
x 2 x 5
vi y log10 6 x
dy
6
dx log 10 6 x
1
x log 10
y log x 5 log x 2
dy
1
1
dx x 5 x 2
x 2 x 5
x 5 x 2
3
x 2 x 5
Exercise 12B; 1acf, 2chk, 5acehi, 6b,
7ad, 8acef, 9bd, 10ac, 11, 13a, 14bdfhjl,
15b, 18bdf, 19b, 20af*, 21a*
Exercise 12C; 1bdf, 2, 3, 6, 7a, 8, 11,
13, 14, 18*