Question

If the sin 30 is 1/2, then the cos and it has a blank an equal sign and another blank

Answer 1

Sine and Cosine are `co-functions`.

\[\Large\rm \sin(\theta)=\cos(90-\theta)\]
So if \(\Large\rm \sin(30)=\frac{1}{2}\)

Then, \(\Large\rm \cos(90-30)=?\)

Answer 2

so 60

Answer 3

???

Answer 4

not to butt in , but this is the second time i have seen a question that starts with
" If the sin 30 is 1/2"
like saying "if two plus two is four, then ..."
it makes no sense

Answer 5

Yah they didn't really give enough information to answer the question :)
But I could see where it was headed lol

Answer 6

That is pretty frustrating.

Answer 7

you can fill it in with literally anything

\[\cos(30)=\frac{\sqrt2}{2}\] or
\[\cos(60)=\frac{1}{2}\] or whatever you like

Answer 8

lol can someone just help me then please

Answer 9

@Samidancer16
Yes,\[\Large\rm \cos(90-30)=\cos(60)\]But relate that back to this:\[\Large\rm \color{royalblue}{\sin(\theta)=\cos(90-\theta)}\]
If we plug in 30 for our angle we get this relationship:\[\Large\rm \color{royalblue}{\sin(30)=\cos(60)}\]

Answer 10

What does that tell you about cos(60)?

Answer 11

so the measurement is 60 for an angle?

Answer 12

Im sorry im bad at this

Answer 13

Just pay attention to the equals sign.
He's telling us a lot.

Answer 14

sin(30) is 1/2, they told us that.
What does that tell us about what cos(60) is equal to? :p

Answer 15

I dont know):

Answer 16

it is not your fault
the question is ambiguous and clearly written by a moron

Answer 17

\[\Large\rm \color{#CC0033}{\sin(30)}=\cos(60)\]Mmk :( ugh
We'll replace our sin(30) with 1/2, since they are equivalent.\[\Large\rm \color{#CC0033}{\frac{1}{2}}=\cos(60)\]Understand what I did?
sin(30) is 1/2. So we rewrote sin(30) as 1/2.

Answer 18

That's what the relationship is telling us.

Answer 19

i dont understand where the60 and the 1/2 is coming from

Answer 20

Sine and Cosine are co-functions. This is just a formula that you'll have to accept for now :)\[\Large\rm \sin(\theta)=\cos(90-\theta)\]The angle we care about is \(\Large\rm \theta=30\)
Plugging that value in is what gives us our relationship.\[\Large\rm \sin(30)=\cos(90-30)\]90-30=60, yes?\[\Large\rm \sin(30)=\cos(60)\]

Answer 21

They told us that:\[\Large\rm \sin(30)=\frac{1}{2}\]That was given to us.

Answer 22

So if:\[\Large\rm \sin(30)=\frac{1}{2}\]and\[\Large\rm \sin(30)=\cos(60)\]What can we say about cos(60)?

Answer 23

okay i get that now where is the 1/2 coming from

Answer 24

ya +_+ weird stuff, ik ik

Answer 25

okay okay nvm

Answer 26

so is the answer 60; 1/2?

Answer 27

For the two blanks? Yes, good, in that order.

Answer 28

okay thank you but how come the 1/2 didnt change?

Answer 29

So you're probably thinking,
well the angle changed from 30 to 60, why didn't the 1/2 change?
But notice that the function also changed from sine to cosine.

So two things changed, and it ended up giving us the same result.
It'd be difficult to explain co-functions without going into some detail and drawing a triangle and all that...

Answer 30

okay well thank you so much