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AP Calculus BC
Unit 3: Differentiation: Composite, Implicit, and Inverse Functions
3.2 Implicit Differentiation
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Cards (20)
What is the key difference between implicit and explicit functions?
Variable isolation
Implicit functions are defined by equations of the form
f(x, y) = 0
Implicit differentiation is required to find
d
y
d
x
\frac{dy}{dx}
d
x
d
y
in implicit functions.
Give an example of an explicit function.
y
=
y =
y
=
x
2
+
x^{2} +
x
2
+
3
3
3
<question_start>x^{2} + y^{2} = 9</latex> is an example of an
implicit
Understanding the distinction between explicit and implicit functions is essential for
implicit differentiation
.
What is an explicit function in terms of variable isolation?
Dependent variable is isolated
What differentiation method is used for explicit functions?
Direct differentiation
What is an implicit function in terms of variable isolation?
Dependent variable is not isolated
What differentiation method is required for implicit functions?
Implicit differentiation
y
=
y =
y
=
x
2
+
x^{2} +
x
2
+
3
3
3
is an explicit function.
x
2
+
x^{2} +
x
2
+
y
2
=
y^{2} =
y
2
=
9
9
9
is an implicit function.
Why is implicit differentiation necessary for certain equations?
Dependent variable cannot be isolated
Steps to differentiate an implicit function
1️⃣ Differentiate both sides with respect to
x
x
x
, apply chain rule to
y
y
y
2️⃣ Rearrange the equation to isolate
d
y
d
x
\frac{dy}{dx}
d
x
d
y
3️⃣ Express
d
y
d
x
\frac{dy}{dx}
d
x
d
y
in terms of
x
x
x
and
y
y
y
An implicit function requires implicit differentiation to find
d
y
d
x
\frac{dy}{dx}
d
x
d
y
.
What does implicit differentiation involve when
y
y
y
cannot be isolated?
Differentiating and rearranging
What rule must be applied to terms involving
y
y
y
during implicit differentiation?
Chain rule
Isolating \frac{dy}{dx}</latex> is a step in
implicit differentiation
.
Find
d
y
d
x
\frac{dy}{dx}
d
x
d
y
for
x
3
+
x^{3} +
x
3
+
y
3
=
y^{3} =
y
3
=
8
8
8
using implicit differentiation.
d
y
d
x
=
\frac{dy}{dx} =
d
x
d
y
=
−
x
2
y
2
- \frac{x^{2}}{y^{2}}
−
y
2
x
2
The derivative
d
y
d
x
\frac{dy}{dx}
d
x
d
y
at a point gives the slope of the tangent line to the curve at that point.