3b Flashcards

1
Q

inverse of a function

A

the result of switching the input and output values of a function

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2
Q

the output of an inverse trigonometric function will be…

A

an angle measure

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3
Q

two ways to represent inverse trigonometric functions

A

1) sin^-1
2) arcsin

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4
Q

why are domains of inverse trigonometric functions restricted?

A

they wouldn’t be functions without the restrictions! (wouldn’t pass the vertical line test! (normal trigonometric functions don’t pass horizontal line test))

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5
Q

to have inverses, a function must pass…

A

the horizontal line test

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6
Q

restricted domain of an sin function

A

[-pi/2, pi/2]

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7
Q

restricted domain of an cos function

A

[0, pi]

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8
Q

restricted domain of an tan function

A

(-pi/2, pi/2)

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9
Q

the restricted domain of a function is the ____ of its inverse function

A

range of possible solutions

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10
Q

restricted domains as shaded on unit circle

A

sin ~ Q1, Q4 (right half)
cos ~ Q1, Q2 (top half)
tan~ Q1, Q4 (right half)

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11
Q

after find solutions of an inverse function…

A

double check they are in the allotted domain!

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12
Q

is sin(x)=1/2 equivalent to arcsin(1/2)=x

A

No, both have pi/6 as a solution but due to the restricted domain of the inverse function that is its only solution whereas the sin function has multiple (infinite) solutions.

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13
Q

since trigonometric functions are periodic…

A

they can have infinitely many solutions (if the domain is not restricted)

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14
Q

general solution to sin(x)=1/2

A

x=pi/6+2pik
and
x=5pi/6+2pik
where k is any integer

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15
Q

general solution to cos(x)=1/2

A

x=pi/3+2pik
and
x=5/3+2pik
where k is any integer

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16
Q

general solution to tan(x)=1

A

x=pi/4+pik
where k is any integer

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17
Q

general solution to all sin and cos functions

A

-find solutions for x on first rotation of unit circle
-write an equation for each with +2pik attached
-clarify k is any integer

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18
Q

general solution to all tan functions

A

-find smallest solution for x on first rotation of unit circle
-write an equation with +pik attached to the solution
-clarify k is any integer

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19
Q

steps to solve trig equations

A
  1. isolate the trig function
  2. find the corresponding angles that satisfy the equation
  3. consider the domain restrictions
    –if note add pik or 2pik
  4. write solutions
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20
Q

REMEMBER WITH SQUARE ROOTS

A

solutions can be +/-

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21
Q

(sinx)^n=

A

sin^nx

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22
Q

[] vs ()

A

[] if </> or equal to (includes end values)
() if strictly </> (does not include max and min values)

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23
Q

steps for solving trig inequalities

A
  1. set f(x)=0 and solve
  2. make a sign chart with you solutions (remember domain restrictions!)
  3. test a value in each interval
  4. interpret the sign chart and answer the inequality
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24
Q

</> signs flip when…

A

you divide by a negative number

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25
secant
sec=1/cos
26
cosecant
csc=1/sin
27
cotangent
cot=1/tan=cos/sin
28
Graphs of sec, csc, cot are undefined where...
sec, csc, tan hit x axis
29
range of sec
(-inf, -1] [1, inf)
30
graph of sec and csc
mini parabolas on top of maxs and mins
31
undefined ares of sec graph
x=pi/2+pik
32
range of csc
(-inf, -1] [1, inf)
33
range of cot
(-inf, inf)
33
undefined areas of csc graph
x=pik
34
undefined areas of cot graph
x=pik
35
cot graph
negative version of tan graph shifted over pi/2, so it fits the new asymptotes of pik
36
to find asymptotes of an equation
plug x and the transformations that directly affect it into the "x" of the equation and solve so x is by itself
37
to solve csc, cot, sec
isolate and change into sin, cos, tan to use unit citcle
38
pythagorean identity
cos^2x+sin^2x=1
39
you can change the pythagorean identity
into a lot! --even tan, if you divide by cos! --to solve for sin^2x or cos^2x
40
sum and diff identities
sin(a+/-b)=sinacosb+/-cosasinb - sign is the same cos(a+/-b)=cosacosb-/+sinasinb - sign changes
41
double angle identities
sin(2x)=2sinxcosx cos(2x)=cos^2x-sin^2x=1-2sin^2x=2cos^x-1
42
polar coordinates
r, theta output, input
43
y =
sin(theta) * r
44
x =
cos(theta) *r
45
r =
+/- sqrt (x^2 + y^2)
46
tan(theta) =
y/x
47
i =
sqrt(-1)
48
complex number rectangular coordinates
a+bi = (a,b)
49
complex number polar coordinates
(rcos(theta))+i(rsin(theta))
50
r(theta) = asin(theta), +/- a?
+ ~ symmetrical to y axis on top - ~ symmetrical to y axis on bottom
51
r(theta) = acos(theta), +/- a?
+ ~ symmetrical to x axis on right - ~ symmetrical to x axis on left
52
if b is even...
graph will have 2 b petals
53
if b is odd...
graph will have b petals
54
if r is positive and increasing, the distance between r and the origin is...
increasing
55
if r is negative and decreasing, the distance between r and the origin is...
increasing
56
if r is positive and decreasing, the distance between r and the origin is...
decreasing
57
if r is negative and increasing, the distance between r and the origin is...
decreasing
58
relative extrema occur
when graph changes from increasing to decreasing or vice versa
59
AROC of a polar function
y2-y1/x2-x1 indicates the rate at which the radius is changing per radian
60
estimating with AROC
f(x) = known y + AROC (x-known x)