Categories: All - inverse - functions - domains - properties

by Rico Tan 12 years ago

405

VM266 0847

VM266 0847

Hyperbolic "Pythagorean" Identities

coth^2 (x) - 1 = csch^2 (x)

1 - tanh^2 (x) = sech^2 (x)

cosh(x) - sinh(x) = 1

VM266 0847

Curious aren't you?

Chapter 10: Improper Integrals

10.4 Integrals with discontinuity in between
10.3 Integrals with infinite limits
10.2 More indeterminate forms
10.1 0/0, inf/inf
L'hopital's Rule
Cauchy's Formula

Chapter 8: Hyperbolics, Inverse Trig

8.4: Inverse Hyperbolic Functions
arc csch x

(d/dx) arc csch x

arc sech x

(d/dx) arc sech x

arc coth x

(d/dx) arc coth x

arc tanh x

(d/dx) arc tanh x

arc cosh x

(d/dx) arc cosh x

arc sinh x

(d/dx) arc sinh x

8.3: Hyperbolic Functions
csch x

csch(x) = 1 / sinh(x) = 2 / (e^x - e^(-x))

Integral of csch u

Integral of csch(x)coth(x) = -csch x + C

(d/dx) csch u

sech x

sech(x) = 1 / cosh(x) = 2 / (e^x + e^(-x))

Integral of sech u

Integral of sech(x)tanh(x) = -sech x + C

(d/dx) sech u

coth x

coth (x) = cosh(x) / sinh (x) = (e^x + e^(-x)) / (e^x - e^(-x))

Integral of coth u

Integral of csch^2 x = -coth x + C

(d/dx) coth u

tanh x

tanh (x) = sinh(x) / cosh(x) = (e^x - e^(-x)) / (e^x + e^(-x))

Integral of tanh u

integral of sech^2 x = tanh x + C

(d/dx) tanh u

cosh x

cosh x = [(e^x) + (e^-x)] / 2

Integral of cosh u

Integral of sinh x = cosh x + C

(d/dx) cosh u

sinh x

sinh x = [(e^x) - (e^-x)] / 2

Integral of sinh u

integral of cosh x = sinh x + C

(d/dx) sinh u

8.1 + 8.2: Inverse Trigonometric Functions
arc csc

If arc csc(x) = y, then csc(y) = x

x must be defined on (-inf, -1] U [0, inf)

y must be defined on [-pi/2, pi/2], hole at 0

(d/dx) arc csc(x) = -1/x(rad(x^2 -1))

i) csc(arc csc(x)) = x; if x is defined on (-inf, -1] U [1, inf)

ii) arc csc(csc(x)) = x; if x is defined on [-pi/2, pi/2], hole at 0

arc sec

If arc sec(x) = y, then sec(y) = x.

x is defined on (-inf, -1] U [1, inf)

y is defined on [0, pi/2) U [pi, 3pi/2)

(1/a) arc sec(u/a) + C

(d/dx) arc sec(x) = 1/x(rad(x^2 -1))

i) sec(arc sec(x)) = x; if x is defined on (-inf, -1] U [1, inf)

ii) arc sec(sec(x)) = x; if x is defined on [0, pi/2} U [pi, 3pi/2)

arc cot

If arc cot(x) = y, then cot(y) = x.

x is defined on (-inf, inf)

y is defined on [0, pi]

(d/dx) arc cot(x) = -1/(1 + x^2)

i) cot(arc cot(x)) = x; if x is defined on (-inf, inf)

ii) arc cot(cot(x)) = x; if x is defined on (0, pi)

arc tan

If arc tan(x) = y, then tan(y) = x.

x is defined on (-inf, inf)

y is defined on (-pi/2, pi/2)

(1/a) arc tan(u/a) + C

(d/dx) arc tan(x) = 1/(1 + x^2)

i) tan(arc tan(x)) = x; if x is defined on (-inf, inf)

ii) arc tan(tan(x)) = x; if x is defined on (-pi/2, pi/2)

arc cos

if arc cos(x) = y, then cos(y) = x.

x is defined on [-1, 1]

y is defined on [0, pi]

(d/dx) arc cos(x) = -1/rad(1 - x^2)

i) cos(arc cos(x)) = x; if x is defined on [-1. 1]

ii) arc cos(cos(x)) = x; if x is defined on [0, pi]

arc sin

If y = arc sin(x), then sin(y) = x.

domain of arc sin [-1, 1]

range of arc sin [-pi/2, pi/2]

arc sin(u/a) + C

(d/dx) arc sin(x) = 1/rad(1 - x^2)

Properties

i) sin(arc sin(x)) = x; if x is defined on [-1,1]

ii) arc sin(sin(x)) = x; if x is defined on [-pi/2, pi/2]

Chapter 7: Inverses, Ln, e

7.5: Exponentials
(d/dx) log base a of x
e as a limit
a^x = e^(xln(a))

integrals of a^x and a^u

integral of a^x = (1/ln(a)) * a^x + C

integral of a^u = (1/ln(a)) * a^u + C

(d/dx)a^x = (a^x) ln(a)

7.4: Integration
Derivations of integral of trig functions

csc(u)

sec(u)

tan(u) and cot (u)

integral of e^x

integral of e^u

integral of 1/x

integral of 1/x = ln(x) + C

integral of 1/u

7.3: The letter e
Definition of e

e is a positive number where ln(e) = 1 <=> e is the base of ln(x)

e^x

(d/dx) e^x & (d/dx) e^u

Properties of Exponents

1. (e^p)(e^q) = e^(p+q)

2. (e^p)/(e^q) = e^(p-q)

3. (e^p)^q = e^pq

7.2: Logarithms
Logarithmic Differentiation Guildelines

Given a differentiable equation, do the following to differentiate logarithmically:

1. Take ln of both sides

2. Differentiate both sides...IMPLICIT DIFFERENTIATION MAY BE NEEDED ALONG THE WAY

3. Multily by the initial equation.

Ptoperties of logarithms

1. log base x of x => ln(e) = 1

2. log(a) + log(b) = log(ab)

3. log(a) - log(b) = log(a/b)

4. a log(b) = log(b^a)

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More basic stuff: log base a of y = x, then y = a^x

Definition of natural log

The natural logarithmic function is a logarithm with base e.

In addition, it is also found that...

ln(x) = integral {(1/t) dt} from 1 -> x

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If x > 1, ln(x) = integral {(1/t) dt} from 1 -> x

If 0 < x < 1, -ln(x) = integral {(1/t) dt} from x -> 1

integral of ln(x)

Derived using integration by parts!!!

(d/dx) ln(x) = 1/x

Shortcut proof:

1. By defn of ln's, ln(x) = integral {(1/t) dt} from 1 -> x.

2. ln(x) must be differentiable because it is the antiderivative of something (1/t)

3. (d/dx) ln(x) = (d/dx) integral {(1/t) dt} from 1 -> x

4. (d/dx) ln(x) = 1/x, the derivative of an integral of a function is the function itself.

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(d/dx) ln(u) = (1/u)du

proof:

1. let y = f(x) = ln(u)

2. (dy/dx) = (dy/du)(du/dx)

3. f'(x) = (d/du) ln(u) * du

(d/dx) ln(u) = u'/u

integral of (1/u) du = u'/u; given that u is a function.

Proven from chain rule of (d/dx) ln(x)

(d/dx) ln(u) = (d/du) ln(u) * (du/dx) = (1/u)du

7.1: Inverses
Inverse Function

The inverse of a function that maps from D -> R is the function that maps from R -> D.

Let y = f(x) be a 1 - 1 function that maps from D - > R. A function g is the inverse of f where the R(f) = D(g) and D(f) = R(g).

Therefore, y = f(x) <=> x = g(y)

The inverse function g is denoted as f^-1

Derivative of an inverse fn.

g(f(x)) = x; f(g(x)) = y

If g is the inverse of f, then...

i) g(f(x)) = x for every x in D(f)

ii) f(g(x)) = x for every x in R(f)

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Ver1 proof is set as hyperlink

Ver2 proof URL: http://i1321.photobucket.com/albums/u556/radicaldreamer18/Calculus%202%20Chapter%207/IMAG0299_zps9a60cf31.jpg

1-1 Functions

1 - 1 functions are functions that never takes the same value twice.

More formally:

1. Let f be a function that maps from D -> R

2. For every x in D, there exist a unique R.

- Let x1, x2 be in D

- f(x1) is not = f(x2)

NOTE:

A) #2 implies the converse: for every y in R, there exist a unique x in D

B) Graphically, a function is 1 - 1 if a horizontal line never intersects the function's curve twice.

Every increasing/decreasing function is 1 - 1

Chapter 9: More integration

9.6 Other substitution tricks
9.5 Integrals with Quadratic Expressions

1. Look for a quadratic equation in the integrand.

2. Complete the square.

3. a. set u = the perfect square from the completed square

b. solve for x using u.

4. plug in u accordingly and and x as well

5. evaluate integral

9.4 Integrls of Rational Functions
Use partial fractions then evaluate integral
9.3 Trig. Substitions

x = a sinb if rad(a^2 - x^2) is in the integrand

x = a tanb if rad(a^2 + x^2) is in the integrand

x = a secb if rad(x^2 - a^2) is in the integrand

9.2 Trig. Integrals of different powers
Subtopic
9.1 Integration by Parts

integral of (u dv) = uv - integral of (v du)