Question

Evaluate? help @amistre64 @ganeshie8 @SolomonZelman @Compassionate

Answer 1

\(\large\cos(\arctan\frac{3}{4})\)

Answer 2

Is it 4/5?

Answer 3

Evaluate
\(\large\cos(2\pi+\arctan\frac{4}{3})\)

Answer 4

the first one, yes is 4/5.

Answer 5

the second one too. 4/5

Answer 6

The second one too? Can you show me how?

Answer 7

@SolomonZelman

Answer 8

Ohh, I did, arctan(3/4) instead of 4/3, lol (for the second one)

Answer 9

\(\normalsize\color{black}{ \cos\left\{ 2\pi+\arctan( \frac{4}{3}) \right\}=\cos(2\pi ) \cos\left\{ \arctan( \frac{4}{3}) \right\}-\sin(2\pi ) \sin\left\{ \arctan( \frac{4}{3}) \right\} }\)

Answer 10

Using the cos(a+b) rule.
Tell me what you get after simplifying this expression?

Answer 11

umm....?

Answer 12

Well, you know that \(\normalsize\color{black}{ \cos(2\pi)=-1 }\) and \(\normalsize\color{black}{ \sin(2\pi)=0 }\)

Answer 13

If you need help, tag me back into the question.

Answer 14

Simplified to this?
\(\large -\cos({\arctan\frac{4}{3}})\)

Answer 15

yes;)

Answer 16

omg, thanks so much. I got -0.6

Answer 17

yes:) that's correct!

Answer 18

wait..could it be 0.6? cause -0.6 isn't an answer choice.

Answer 19

It is -0.6, because the `cos(2π)` by which you multiplied, is -1.
So it should be -0.6, not positive. I am failry sure.

Answer 20

that in a box, is cos 2 pi.

Answer 21

maybe the answer choice forgot the minus sign...

Answer 22

well, that is what you should talk to your teach about. Or maybe some info is missling. Like it has to be in first quadrant or something like this?

Answer 23

idk...questions at my school are really poorly written

Answer 24

but this is all you had?
To evaluate,
cos( 2pi + arctan(4/3) ) /

Answer 25

(the slash shouldn't be there)

Answer 26

yes, it is

Answer 27

"evaluate" and then that equation