Question

What is 2 pi/5 radians in degrees?

Answer 1

72 degrees

Answer 2

because you change pi radians to 180 degrees, so 2(180)/5 = 72

Answer 3

Thanks! The point (3, -4) is on the terminal side of an angle 0 . What is cos 0 ?

Answer 4

(180/pi ) *(2pi/5)=72 degree

Answer 5

cos theta = 3/5

Answer 6

use (pi) radians = 180 degrees

Answer 7

becuase you draw the right triangle in quadrant IV, you see that the hypotenuse is 5 from Pythagorean Theorem

Answer 8

If tan 0 =12/5 and cos 0 < 0, what is sin 0 ?

Answer 9

lol

Answer 10

sin theta = 5/13

Answer 11

draw the 5-12-13 triangle

Answer 12

you are a genius

Answer 13

What is tan 3pi/2 ?

Answer 14

that is tan (120) = - tan 60 = - sqrt(3)

Answer 15

Note: error

Answer 16

that is tan (270) which is undefined

Answer 17

3pi/2 = 3(180)/2 = 270

Answer 18

so tan (270) is undefined.

Answer 19

What is the reference angle for 120°?

Answer 20

60?

Answer 21

It is 60 degrees.

Answer 22

Which expression is equivalent to (1 – sin2 x)(sec x)?

Answer 23

you are currently helping me graduate high school! THANK YOU!

Answer 24

welcome.

Answer 25

(1-sin^2x) = cos^2 (x)

so you have cos^2(x)(sec x) = cos x

Reason is that sec x = 1/cos x
and you should know that 1- sin^2(x) = cos^2(x)

Answer 26

Final answer is cos x as I showed above.

Answer 27

Which expression is equivalent to cot t sec t?

Answer 28

csc t, sin t, tan t, sin^2 t, csc^2 t ?

Answer 29

cot t = cos t/sin t

and sec t = 1/cos t

so cot t sect t = (cos t/sin t) times 1/cos t = 1/sin t = csc t

Answer 30

it's csc t?

Answer 31

yes

Answer 32

Which function has a phase shift of pi/2 the right?

Answer 33

choices?

Answer 34

one second

Answer 35

I assume you are looking for cos x

Answer 36

because when you shift sin x pi/2 to the right you get cos x

Answer 37

y = 2sin(1/2x+pi), y = 2sin(2x +pi),

y = 2sin(x +pi/2),y = 2sin(x -pi) , y = 2sin(2x -pi)

Answer 38

each options is separated by commas

Answer 39

y = 2sin((x+pi/2)

Answer 40

x + pi/2 = 0 gives you x = -pi/2

Answer 41

What is the domain of y = cot x?

Answer 42

x cannot be 0,180, 360 or any multiple of 180

Answer 43

because cot x = cos x/sin x

so a fraction is undefined when the denominator is zero

sin x = 0 when x = 0, 180, 360, etc...

Answer 44

none of my options are 'undefined'

Answer 45

(-infinity, infinity), (0, pi), all x= pi/2+pi, all x= pi, all x=pi/2

Answer 46

those are my options

Answer 47

poorly written choices

Answer 48

You want the domain...the domain is all possible values that x can be

Answer 49

the best choice would be (0,pi)

Answer 50

domain exists on (0,pi)

Answer 51

yeah this things sucks. .. Simplify the expression: 1/1+cot^2 x

Answer 52

1 + cot^2(x) = csc^2(x)...

Answer 53

so 1/csc^2(x) = sin^2(x)

Answer 54

Final answer is sin^2(x)

Answer 55

Makes sense?

Answer 56

Given tan 0= 4/3 and sin=(-4/5), find cos 0

Answer 57

yeah. how are you so good at this?

Answer 58

tan theta = sin theta/cos theta

so, 4/3 = -4/5/cos theta

so cos theta = - 3/5

Answer 59

got it?

Answer 60

Solve 2cos2x + cosx − 1 = 0 for x over the interval [0, 2.pi. yes!

Answer 61

This is a trig equation..I will work it out step-by-step...watch

Answer 62

k

Answer 63

are you a math teacher?

Answer 64

We first factor:

(2cos x - 1)(cos x + 1) = 0

Set each factor equal to 0, we get:

2 cos x - 1= 0, so cos x = 1/2, and x = pi/3 and 5pi/3
cos x + 1 = 0, so cos x = -1, so x = pi

Answer 65

x = pi/3, pi, and 5pi/3

Answer 66

makes sense

Answer 67

Do you understand?

Answer 68

yes.. this is the last one to my test.... Which expression is equivalent to tan(-x)cos2x?

Answer 69

choices?

Answer 70

-sin xcos x, sin xcos x, tan x + sin2x, tan x − sin2x, -tan x − sin2x

Answer 71

tan(-x) = - tan x
cos(2x) = many formulas..

Are you typing your question correctly? I dont see it

Answer 72

check the question again

Answer 73

yeah.. I even copied and pasted it

Answer 74

http://learner.ple.platoweb.com/Assessment/Launch?UserAssignmentId=23240609&resourceNodeId=45078331&assessmentActivityId=1464179&assessmentTypeId=2&assignmentId=3371589&classId=706599&contentLicenseType=1

Answer 75

I cant open the document

Answer 76

is it cos(2x) or cos^2(x) in your question?

Answer 77

oooh you know why because all of the options are supposed to be a ^ in front of the 2

Answer 78

oh...see, I told you something was wrong

Answer 79

so retype your question and the choices

Answer 80

I'll be back in 3 minutes...will see your question and choices when I return

Answer 81

Which expression is equivalent to tan(-x)cos2x?



-sin xcos x
sin xcos x
tan x + sin^2x
tan x − sin^2x
-tan x − sin^2x

Answer 82

sorry...I still dont see it. Assuming you typed the question correctly.

Answer 83

I believe there's an error in the question

Answer 84

Or I just dont see it

Answer 85

what do you think the closest option is?

Answer 86

we do know that,
tan(-x) = - tan x

Answer 87

and we know that cos(2x) = 2 cos^2(x) - 1 or 1 - 2 sin^2(x)

Answer 88

In this type of question, I cannot eliminate any choice

Answer 89

so it's one of the tans?

Answer 90

I dont want to second guess

Answer 91

Not necessarily..could be any of the choices...are you sure that you typed the question correctly?

Answer 92

Or just post this question, maybe someone will see it.

Answer 93

I think you meant cos^2(x) in the question!

Answer 94

you typed cos (2x)

Answer 95

If it's cos^2x, then its easy

Answer 96

If it's cos^2(x), then it is - sin x cos x

Answer 97

are you there?

Answer 98

Thanks!