4 3x
ln y ln x ln e ln tan x
4 3x
2
dy 1 4 sec x
3
dx y x tan x
2
dy 4 sec x
x e tan x{ 3
4 3x
}
dx x tan x
,3. y x sin 2 x cos 4 x
5
ln y ln x ln sin 2 x ln cos 4 x
5
dy 1 1 1 1
5 .5 x
4
2 cos 2 x . 4sin
dx y x sin 2 x cos 4 x
dy 1 1 1
y{ 5 .5 x
4
2 cos 2 x . 4si
dx x sin 2 x cos 4 x
dy 5
x sin 2 x cos 4 x{ 2 cot 2 x 4 tan 4 x}
5
dx x
, Implicit function
If y=𝒙𝟐 − 𝟒𝒙 + 𝟐, 𝒚 is completely defined in terms of x, and y is c
explicit function of x.
When the relationship between x and y is more involved, it may n
possible(or desirable) to separate y completely on the LHS , e.g. x
=2. In such a case as this, y is called an implicit function of x, bec
relationship of the form y=f(x) is implied in the given equation.
it may still be necessary to determine the derivatives of y with re
x and in fact this is not at all difficult.