Question

Need some help, can someone explain this problem?

Answer 1

i can help. :)

Answer 2

well, maybe i can help. XD

Answer 3

To clarify, I already know the answer is 70, but can someone explain this:
If: \[\cos^{-1} \frac{ 342 }{ 1000 }\] then what is m<A to the nearest degree?

Answer 4

Not sure if you'll need to explain;

Answer 5

Are you saying:

If

\(cos^{-1} = \dfrac{342}{1000}\)

Answer 6

Yes.

Answer 7

But it's asking for m<A to the nearest degree. I already know it's 70, but I don't know how they got it.

Answer 8

Is the problem "find the measure of angle A tot eh nearest degree?"

Answer 9

Well, let's see..\(\cos^{-1}\) is the inverse of cosine..and we do this rule when we don't know what the angle measurement is..

So:

\(\cos^{-1} = \dfrac{342}{1000}\) is solving for the angle measurement..

\(\sf cosine = \dfrac{Opposite}{Hypotenuse}\)

Therefore, 342 must be the length of the Opposite, and 1000 the length of the Hypotenuse.

342 / 1000 = 0.342

Plug this into your calculator and find the inverse of sine:

I get about 20..Idk why..lol.

Answer 10

Maybe you can explain @mathstudent55

Answer 11

Cosine is adj/opp, not opp/hyp

Answer 12

Ohh..I was thinking Sine.. my bad.

Answer 13

@Nibby How exactly was the problem given to you?

Answer 14

So 342 must be adjacent, and 1000 must be opposite..

Answer 15

It fits!

Answer 16

No. 1000 is hypotenuse.

Answer 17

Oops, so many mistakes.

Answer 18

Anyway, 342/1000 = 0.342, plug that in the inverse of cosine and you get 70 degrees!

Answer 19

I think I gave you guys the problem in the wrong form... Oops.
Here;

Answer 20

sin x = opp/hyp
cos x = adj/hyp
tan x = opp/adj

Answer 21

http://www.rapidtables.com/calc/math/Arccos_Calculator.htm

Answer 22

Well, let's see..\(\cos^{-1}\) is the inverse of cosine..and we do this rule when we don't know what the angle measurement is..

So:

\(\cos^{-1} = \dfrac{342}{1000}\) is solving for the angle measurement..

\(\sf cosine = \dfrac{Adjacent}{Hypotenuse}\)

Therefore, 342 must be the length of the Adjacent, and 1000 the length of the Hypotenuse.

342 / 1000 = 0.342

Plug this into your calculator and find the inverse of cosine:

http://www.rapidtables.com/calc/math/Arccos_Calculator.htm

And you get 70 degrees.

Answer 23

Understand now? @Nibby

Answer 24

Not entirely, sort of.

Answer 25

@Nibby We don't write sin, cos, or tan alone. We write cos x, tan A, etc.
In your problem, you should write

\(\cos A = \dfrac{342}{1000}\)

Then \(A = \cos^{-1} \dfrac{342}{1000}\)

This is the inverse cosine function. The inverse cosine of 342/1000 is asking the question "what angle has a cosine of 342/1000.

Answer 26

Now you enter the fraction in your calculator.
Just actually divide 342 by 1000 to get 0.342
Then you press the second function key (or inverse key) followed by the cosine key to find the inverse cosine.

Answer 27

I don't have a physical calculator; can you do this using Microsoft's calculator?

Answer 28

I already gave you the link to another calculator..just plug in 0.342 into it..

Answer 29

Ah, okay. Thanks.

Answer 30

Thanks guys, I understand it a bit more now.