CALCULUS
By: Vanessa F.
EXPONENTIAL & TRIGONOMETRIC
WITH DERIVATIVES
Exponential
f(x) = e^x, then f'(x) = e^x
g(x) = e^h(x), then g'(x) = e^h(x) . h'(x)
Logarithmic
The function for this is log power over base
e^in x= x
Derivatives
If f(x) = b^x then f'(x). b^x . In b
If g(x) = b^h(x) then g'(x) = b^h(x) . In b . h'(x)
Trigonometric
If f(x)= sinx then f'(x) = cos x
If f(x) = cos x then f'(x) = -sinx
If f(x) = tan x then f'(x) = sec^2 x
also, tanx = sinx/cosx
ex, y= (sinx + tan x)^4
dy/dx= 4 (sinx + tanx)^3 . (cos + sec^2x)
= 4 ( cosx + sec^2 x ) ( sinx + tanx)^3
INTRODUCTION
Radical Expressions
√a x √a = √a2 = a
(a - b) (a+b) = a2 - b2
( √m - √n ) ( √m + √n ) = √m2 - √n2 = m - n
If the expression is the
numerator, rationalise by
multiplying the numerator
and denominator by its
conjugate.
If the expression is in the
denominator, rationalise by
multiplying the numerator and
denominator by its conjugate.
when there is no denominator,
simplify.
MINOMIAL
Slope of a Tangent
lim f ( a + h ) - f (a) / h
h→0
Rates of Change
Instantaneous Velocity
Instantaneous Rate of Change
< Slope of the tangent
Average Rate of Change
< Slope of the secant
Limits
Indeterminate form 0/0
ONE SIDED LIMITS if it is a absolute value
CHANGE OF VARIABLE if there a cube roots or other
RATIONALISING if there is a square root
FACTORING if there is a restriction
Limit exists if both one-sides limits
are the same
Limit D.N.E if the one-sides limits
are not the same
The number L = the limit of the function
y = f(x) as x approaches the value 'a'
Continuity
Function is continuous when
limit of f(x) = f(a)
both side limits are equal
f(a) is defined
SECOND DERIVATIVES
Optimization Problems
Solving Steps:
- Define variables
- Make an equation that defines the question
- Apply any substitutions if needed
- Set the derivative to 0
- Find the critical values
- Find the test values
- Find the domain and range
Ex, A piece of cardboard, 80 cm by 40 cm,
is used to make an open-top rectangular box.
Find the dimensions for the box with the largest volume.
First I would draw a diagram
to better understand the question.
Then I would let x represent the width
of the removed square.
For this particular question, I would use
the formula V = (L)(W)(h)
I then plug the number given in the question
into this formula and find the first derivative.
I ten set the derivative to 0. Once i find the
critical value, I find my test values and the dimensions.
Extreme Values
Critical Values
f'(c) = 0 or f'(c) D.N.E
Minimum
Local min
- the second lowest point on a
graph
Absolute min
- the highest point on the graph
Maximum
Local max
- the second highest point on a
graph
Absolute max
- the highest point on a graph
To find the max and min on an interval:
- Differentiate
- Set f'(x) = 0
- Solve of x in f'(x) = 0 or where f'(x) D.N.E
- Test values
- Compare the tested values
Velocity and Acceleration
The function notation for the
second derivative is considered
as, f''(x)
To find the second derivative,
You have to find the first derivative
of the function being given.
ex, f(x) = 2x^2 + 5x + 6
f(x) = 4x + 5
f''(x) = 4
Therefore, the second derivative is 4.
Velocity
v(t) = s'(t)
The instantaneous rate of change
of the position function s(t)
-If the object is moving up or right,
the v(t) is > 0
-If the object is moving down or left,
the v(t) is < 0
- If the object is at rest, v(t) = 0
Acceleration
a(t) = v'(t) = s''(t)
The instantaneous rate of change
of the velocity with respect to time
This is known as the second derivative
of the s(t) and first derivative of v(t)
FIRST DERIVATIVES
Composite Functions
Defined as (f. g) = f(g(x))
Chain Rule
h'(x)= f'(g(x)) . g'(x)
Lebniz Notation
dy/dx = dy/du - du/dx
Quotient Rule
f'(x) = p'(x) . q(x) - p(x) . q'(x)/ [q(x)]^2
Product Rule
f'(x) = p'(x) . q(x) + p(x) . q'(x)
Power of a Function Rule
f'(x) = n[g(x)] ^n-1 . g'(x)
Polynomial Functions
Lebniz Notation
f(x) = f'(x)
y' = dy/dx
Sum and Differences Rule
f(x) = p(x) +- q(x), then f'(x) = p'(x) +- q'(x)
Constant Multiple Rule
f(x) = k [g(x)], then f'(x) = K [g'(x)]
Power Rule
f(x) =x^n, then f'(x) = nx^n-1
Constant Function Rule
f(x) = k, then f'(x) = 0
Horizontal Tanget
When the slope of a tangent is at 0
The Function
f'(x)
Function f(x) is differentiable
only if f'(a) exists
Its not differentiable if f(x) is
- Cusp
- Vertical Tangent
- Discontinuity
- Corner
f'(x) is always one degree
less than f(x)
f'(x) = lim f ( a + h ) - f (a) / h
h→0
CURVE SKETCHING
Increasing and Decreasing
Functions
Function is increasing if,
f(x1) < f(x2) when x1 < x2
Function is decreasing if,
f(x1) > f(x2) when x1 < x2
To find the values on inc/dec,
use a interval chart
First Derivative Test
If f'(x) changes from + to - , f has a local max
If f'(x) changes from - to +, f has a local min
If f'(x) sign does not change then the max and min D.N.E at c
Critical Points
A critical value is also
known as c
if the value is f(x) and f'(c) = 0 or f'(c) it is undefined
To find the critical values of a function,
Make the first derivative of the function
equal to 0.
VA, HA and OA
Vertical Asymptotes (VA)
Domain restriction is, x is not = to ...
Is determined by factoring the numerator
and denominator of rational expressions
Horizontal Aysmptotes (HA)
To determine limits as x approaching
infinity of a rational function, divide the
numerator and denominator by the highest
degree then simplify
Oblique Asymptotes (OA)
If the degree on the numerator
is one degree higher than the
denominator
To determine OA,
use long division
Concavity/ P.O.I
If f''(x) > 0 then f(x) is concave up
( also known as a curve facing up)
If f''(x) < 0 then f(x) is concave down
( also known as a curve facing down)
The Point of Inflection is defined if
f''(x) changes sign at x.
Second Derivative Test
If f'(c) + 0 and f''(c) > 0, then local min a c
If f'(c) and f''(c) < 0, then local max at c