Question

I DON'T GET IT
How is either method wrong? - (the plus minus sign wasn't an option in their symbols bank?)
http://prntscr.com/8ft0nc
http://prntscr.com/8ft0se

Answer 1

\[\sqrt{4-(2\sin \theta)^2}\]\[\sqrt{4-4\sin^2\theta} \]\[\sqrt{4(1-\sin^2\theta)}\]and 1-sin^2(theta)=cos^2theta
so we get
\[\sqrt{4\cos^2\theta}\]=\[\pm2\cos \theta\]

Answer 2

I got that. The system isn't taking the answer in any form...

Answer 3

wait :D i didn see this - \[0<\theta <90\]

Answer 4

I tried these combinations\[\pm\sqrt{4\cos^{2}\theta}\]\[\sqrt{4\cos^{2}\theta},-\sqrt{4\cos^{2}\theta}\]yes? what does this mean?\[0\lt\theta\lt90?\]

Answer 5

that means that the angle theta lies between 0degrees and 90 deegrees

Answer 6

Yes ?
I don't know what that applies to my answer lol, don't know how to

Answer 7

hav u tried this-
\[2\cos \theta\]

Answer 8

tried that as the answer?

Answer 9

http://prntscr.com/8ft6av?

Answer 10

?

Answer 11

I have tried the positive version already. I have only one attempt left.
However, I solved by hand and the answer I got was\[\pm2\cos\theta\]

Answer 12

I mean\[\pm2\left|\cos\theta\right|\]

Answer 13

yea

Answer 14

I don't get it.
See, I got this one right without issues. http://prntscr.com/8ft75p

Answer 15

Maybe they are negative?

Answer 16

I can't risk the attempt though, got to make sure. :S

Answer 17

:) if they r not accepting positive then no scope for negative

Answer 18

maybe theres some error in their server

Answer 19

"No scope"?? -Confused-
Yes maybe. One time I put space after a comma and they told me it was wrong. Someone on here said "take the space out" and I got it right after that... =_=

Answer 20

hahaha :D these things r annoying
have u tried it like this- http://prntscr.com/8ft8mg
i mean that space between theta nd that sec or tan or whateva

Answer 21

Sadly I tried it before, doesn't register as a trig function if I do that

Answer 22

have tried any such question before ...a question in which the answer was in the form of a trigo expression?

Answer 23

que?

Answer 24

i would try \( 2| \cos \theta| \) for 1st
and \(3\tan \theta \) for 2nd

Answer 25

i mean \(3 |\tan \theta |\)

Answer 26

@hartnn first one does not accept
second one I cannot try, I must be sure - only one submit attempt left ^^; sorry!

Answer 27

its definitely not \(\pm\)
the answer to a \(\sqrt{...}\) is always a positive

Answer 28

yes maybe it doesn't accept because of that bracket u put :P http://prntscr.com/8ftchw

Answer 29

The coding comes with the bracket. @imqwerty I cannot remove that. I have tried that.

Answer 30

@hartnn I was taught that there are two types of signs to a square root? I mean (-)(-)=+ right?

Answer 31

u must consult ur teacher

Answer 32

HAHAHAHHA my teacher is dumb she won't help me, I've tried. She sucks at technology and give us online homework LOL

Answer 33

if already not tried,
\(3 |\tan(\theta)|\) is worth trying for 2nd.

don't forget to keep the fingers crossed :P

Answer 34

ehhh.
I have done that?

Answer 35

lol

Answer 36

is this flvs? maybe u get the solution to this issue on google :)

Answer 37

if x^2 = a
then
x = \(\pm \sqrt a\)

thats because \((\sqrt a)^2 \\ and \\ (-\sqrt a)^2 \\ \text{both equal a}\)

Answer 38

and \(\sqrt a\) is just one of them, and it can never be negative

Answer 39

????????

Answer 40

Ah my question key die from pressing too much LOL x_x!

Answer 41

was just trying to explain why sqrt a can never be negative

Answer 42

so u got the 1st one wrong ....did it tell u the correct answer afterwards?

Answer 43

@imqwerty No, it does not tell me the answer. :[
@hartnn I am still lost, what o-o

Answer 44

...My computer is very laggy right now

Answer 45

:)

Answer 46

go for \(3|\tan \theta |\) !

Answer 47

...Fine, I blame you guys if I fail the question lol

Answer 48

http://prntscr.com/8ftleb
... @hartnn it's wrong.

Answer 49

I don't get iiiit! D:

Answer 50

the system should atleast take equivalent answers..
seems to be a faulty system, and an incorrect way to test students!


maybe it would have accepted
\(|3 \tan \theta |\)

Answer 51

The teacher said the answer must be a|cos theta| format

Answer 52

it needs to have cos in ti ??

Answer 53

no that is an example trig function

Answer 54

sec^2 x = 1/cos^2 x

Answer 55

LOL

Answer 56

3 | tan \(\theta \)| is indeed in that format

Answer 57

Yeah idk why they say it's wrong. This question have the right format http://prntscr.com/8ftnwx

Answer 58

@hartnn \[\sin10=\cos{?}\]

Answer 59

10 degree

Answer 60

Wait never mind

Answer 61

I got it

Answer 62

sin x = cos(90-x)

here x = 10

whats 90 -10 ?

Answer 63

ok

Answer 64

lolol sorry

Answer 65

no problem :)

Answer 66

But I don't get the formatting of those problem, confusing D:

Answer 67

Also: "Use Definition II to explain why it is possible to find an angle θ that will make tan θ as large as we wish" (what?!)

Answer 68

@hartnn ? ?

Answer 69

whats the Def II?

they are asking why tan 90n goes to infinity or -infinity

Answer 70

Yes.
And I got wrong answer here too LOL very sorry

(8 cos 30°)2 I put 96 is wrong

Answer 71

^2 sorry not x2

Answer 72

cos 30 = sqrt 3/2

8 cos 30 = 4 sqrt 3

its square
16*3 = ...

Answer 73

:o
Oh um um um

Answer 74

UM.... 48?!

Answer 75

yes

Answer 76

lol! I got it :D

Answer 77

Thank you ! :]

Answer 78

welcome ^_^

Answer 79

But... what about the weird question? Do I just skip it for now? o-o

Answer 80

take 2nd opinion...
maybe ask some other expert

or you can skip it, if you're not in any hury

Answer 81

Okay.

Answer 82

@hartnn Sorry question: http://prntscr.com/8ftxg2 ?

Answer 83

cos 30 = sqrt 3/2

cos^2 30 = 3/4


4cos^2 30 = 3

Answer 84

6 sin 30 = 6/2 =3

Answer 85

finally, 3+3 =6

Answer 86

o_o Oh.

Answer 87

So I should not do it the quadratic formula way yes?

Answer 88

Too complex? lol

Answer 89

you can, but that not required, because we know the values already

Answer 90

ah ok. got it

Answer 91

−5 sin 2x if x = 30, how much?
I don't know how to do a sin b x

Answer 92

x = 30,
so 2x = 60

sin 60 = sqrt 3/2

so -5 sqrt 3/2

Answer 93

OOOOOOH okay! Thank you :)

Answer 94

Umm last one, this really confusing me http://prntscr.com/8fu4ew?

Answer 95

?

Answer 96

@hartnn

Answer 97

tan is opposite/adjacent so it has to be the 1st one only