Study Flashcards

1
Q

Why is 3ln(1/2) < 2ln(1/2)?

A
3ln(1/2) = 3ln(2^-1)=-3ln(2)
and 2ln(1/2)=2ln(2^-1)=-2ln(2).

-3ln(2) < -2ln(2)

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2
Q

If a function has a curved top what is the interval?

A

Closed

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3
Q

An interval is closed when asked to find where a function is increasing/decreasing when

A

The top is rounded

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4
Q

Why is sin^-1(sin 4π/3) = -π/3?

A

sin(π-θ)= sin, so:

sin(π-4π/3)=sin(-π/3) which is in the range of sin^-1.

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5
Q

sin(π-θ)= sin, so:

sin(π-4π/3)=sin(-π/3) which is in the range of sin^-1.

A

sin^-1(sin 4π/3) = -π/3

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6
Q

What does it mean to find a domain where f is one-to-one?

A

Find where it is defined

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7
Q

Simplify with exponent rules:

√a √b/ √ab

A

a^1/6 / b^1/12

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8
Q

Find domain:

h(x)=1/ ^4√x^2 -5x

A

(-∞, 0) U (5, ∞) because x(x-5)>0 is equal to x<0 and x>5

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9
Q

Find domain:

f(x)= √16-x^4 / x^2 -1

A

[-2,-1)U(-1,1)U(1,2] because x cannot equal +-1 and x<=+-2 which equals -2<=x<=2

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10
Q

If a function is always decreasing, never zero, and f(-2)=1 and f(1)=2, what is the graph?

A

A piecewise function.

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11
Q

What does cos(-x) equal?

A

cos(x)

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12
Q

What does sin(-x) equal?

A

-sin(x)

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13
Q

Equals -sin(x)

A

sin(-x)

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14
Q

Simplify:

2x(4-x)^-1/2 - 3√4-x = 0

A

x=12/5 because you put (4-x)^-1/2 under 2x and ass 3√4-x to right side. Then solve for x.

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15
Q

How is this absolute value function solved?:

3|x-4|=10

A

|x-4|=10/3

Then x-4=10/3 and x-4=-10/3

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16
Q

Simplify:

3x^3/2•y^3 / x^2•y^-1/2

A

9y^7 / x because you multiply all exponents by 2 first. Then any negative exponents are flipped and solve.

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17
Q

How is this simplified?

√200 - √32

A

Split into one non-squarable and squarable:

√2 • √100 - √2 • √16

√2 • 10 - √2 • 4

6√2

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18
Q

Evaluate:

y/x - x/y / 1/y - 1/x

A
  • (y+x) because (y+x)(y-x) / x-y =

- (y+x)(x-y) / x-y

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19
Q

How is this evaluated?:

16^-3/4

A

Equals 1/(16^1/4)^3

1/2^3

1/8

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20
Q

How do you prove:

√x^2 = x

A

√(-2)^2 = -2 so false

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21
Q

How do you prove:

a^2+b^2=c^2

A

(1)^2+(2)^2=(3)^2 so false

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22
Q

How do you prove:

√xy

A

Equals √x•√y

x^1/2 • y^1/2

(xy)^1/2 = √xy so true

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23
Q

If the half-life is 4 days, what is the mass after 16 days?

A

(1/2)^t/4 where t is days and 4 is half-life

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24
Q

Difference between rational and algebraic equations

A

Rational has polynomial on numerator AND denominator

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25
Rational has polynomial on
numerator AND denominator
26
Evaluate this log: log(5)(200/8)
log(5)(25) so 2
27
Solve for x: 2^x = 5^3x+7
x=7ln(5) / ln(2) - 3ln(5) because you take exponent out and distribute.
28
If you have domain and need range, what is done?
Test values of domain for highest and lowest values of range.
29
Test values of domain for highest and lowest values of range.
If you have domain and need range
30
Why is cos^-1(-1)= π?
Because cosine hits -1 every π
31
Because cosine hits -1 every π, this means the inverse would be.
cos^-1(-1)= π
32
What is the domain of ln(x)<0?
3^ln(x)
33
Definition of one-to-one funct
Function that never takes on the same value twice
34
Function that never takes on the same value twice
One-to-one
35
Find exponential function given two points: | 1,12) and (3,108
12=C(b^1)=Cb 108=C(b^3)=Cb^3 C=12/b (solve for C) 108= 12/b•(b^3)=12b^2 (plug in C in second) b=3 (solve for b) C=12/3 = 4 so, y=4(3)^x
36
How is number e defined?
The value so that the slope of the tangent like to y=e^x at (0,1) is exactly 1.
37
The value so that the slope of the tangent like to y=e^x at (0,1) is exactly 1.
e
38
How is this divided?: 9^3 / 3^-8
Flip 1/9^3 / 1/3^8 1/9^3 • 3^8 3^8 / 9^3 3^8 / (3^2)^3 3^8 / 3^6 3^2
39
The graph of y=1/3x + b is shrunk by a factor of
3 not 1/3
40
Is f(s+t)=f(s)+f(t)?
No because (f+f)(x)=f(x)+f(x)
41
Suppose g is an even function and let h=f o g. Is h always an even function?
Yes because if g = x every time being even, then so is f o g
42
Volume of sphere
4/3πr^3
43
4/3πr^3
Volume of sphere
44
Graph the function y=|x^2 -9|
Same as regular x^2 graph but x’s from -3 to 3 are reflected over x-axis
45
Equation for two families if functions if one family’s is y=5x+b and the other’s is y=m(x-5)+1.
5x+b=m(x-1)+1 and solve
46
If a box has dimensions 18in. by 30in and gets equal squares of side x at each corner folded up, express the new volume as a function of x.
V=lwh so, V=(30-2x)(18-2x)x
47
If the sides of a rectangle box, (not the bases), are the height (h) and the length (2w), and also the width (w), what is the cost of all the sides?
2[2(wh) + 2(2wh)] since the area for 2 sides is 2(wh) total, and the other two sides is 2(2wh) total.
48
If the material for the base of a rectangular box costs $8 per square meter, what is the total cost if w is the width and 2w is the length?
A=lw so, (2w)(w)=2w^2 Multiply 8 by this number for the cost: 8(2w^2)
49
In general, if f(x)=g(x) when x cannot equal a, then
``` lim f(x) = lim g(x) x—>a x—>a ```
50
Substituting limit points directly into functions only works for
Polynomials and rationals
51
Only works for polynomials and rationals
Substituting limit point directly into a function
52
Domain of tan function
nπ/2
53
nπ/2
Domain of tangent function
54
How is cot graphed?
Tangent but backwards
55
Tangent but backwards on graph
Cot
56
Domain and range of cos^-1
R: [0, π] D: [-1,1]
57
Domain and range of sin^-1
D: [-1,1] R: [-2π, 2π]
58
When reflection about a y value, what is done?
Add negative at base and add twice the y-value
59
Add negative at base and add twice the y-value
When reflection about a y value
60
When reflecting about x-values what is done?
Add negative at x and add twice the x-value
61
Add negative at x and add twice the x-value
When reflecting about x-values
62
Order of transformations
``` H-shift H-stretch/shrink Reflect y-axis Vert-stretch/shrink Reflect x-axis Vert-shift ```
63
To find x-values of log function what is done?
Set praenthesis equal to 0, 1, and the base and solve
64
Set praenthesis equal to 0, 1, and the base and solve
To find x-values of log function