Unit 3 - Differentiation: Composite. Implicit, and Inverse Functions Flashcards
Composite function
Function inside another function
Chain Rule is used to find the
Derivative of composite functions
d/dx f(g(x)) =
f’(g(x)) * g’(x)
Explicit equation
Equation that is set to be equivalent to y
Implicit euqation
Equation that is not set to be equal to y
d/dx x =
1
d/dx y
dy/dx
To implicitly differentiate,
1 - take derivative normally, each time a ‘y’ is involved, include a dy/dx
2 - gather all terms with dy/dx on left side, everything else on right
3 - factor out dy/dx if necessary to create only one dy/dx term
4 - solve for dy/dx
To find slope with an implicit derivative,
you need both x and y values
To find equation of a tangent line for an implicitly differentiable equation, you need to
1 - find y and x values
2 - find the derivative using implicit differentiation
3 - use derivative to find slope at points
4 - substitute values into y -y1 = m (x-x1)
Horizontal tangent
Exists when slope is equal to zero
To calculate horizontal tangent for an implicit equation
1 - take derivative and set equal to zero
2 - numerator is equal to zero and solve
3 - substitute x-value into original equation to find y-value
Vertical tangent
Exists when slope is undefined
To calculate vertical tangent for an implict equation
1 - take derivative and set equal to undefined
2 - denominator is equal to zero and solve
3- substitute y-value into original equation to find x-value
Inverse function
Can be found by swapping input and output
Three ways to say that f and g are inverses
f is the inverse of g
g(x) = f-1(x)
f(g(x)) = x and g(f(x)) = x
d/dx [f-1(x)] =
1 / f’ * [f-1(x)]
Inverse trig function notation
notation with a “-1” as in “sin-1(x)”
with prefix “arc” as in arcsin
d/dx sin-1(x) =
1 / square root of (1 - x^2)
d/dx cos-1(x) =
- 1 / square root of (1 - x^2)
d/dx sec-1(x) =
1 / |x| square root of (x^2 - 1)
d/dx csc-1(x) =
- 1 / |x| square root of (x^2 - 1)
d/dx tan-1(x) =
1 / x^2 + 1
d/dx cot-1(x) =
- 1 / x^2 + 1
For inverse trig derivatives,
Use derivative multiplied by derivative of value in parentheses
In order to simplify inverse trig derivatives,
1- determine whether den/nom is pos/neg
2- simply num with den and leave square root alone
3- determine if you need an absolute value
For inverse trig function, the domain and range
of their normal trig function are switched
Higher order derivatives notation
y^(n) or d^ny / dx^n
Second derivative
Derivative of the derivative
When calculating second der. with implicit diff.,
A dy/dx with remain, then you substitute