Question

If sin beta = (-15/17) and beta is in quadrant 4, find cos beta

Answer 1

need help

Answer 2

Yesss!

Answer 3

ok hang on

Answer 4

Thankkkkk you!!

Answer 5

have answer choies

Answer 6

zero, sorry

Answer 7

that the answer

Answer 8

Wait...what is the answer, idgi lol

Answer 9

OH, no that isn't the answer

Answer 10

So our angle is somewhere in the 4th quadrant right?

Answer 11

Let's draw a triangle from this angle. We should be able to label 2 of the sides based on what we know about the sine function.

Answer 12

\[\large \sin \beta \qquad = \qquad -\frac{15}{17} \qquad =\qquad \frac{opposite}{hypotenuse}\]

Answer 13

The only thing we need to be careful about is, where does the negative go?
With the opposite side measure?
Or with the Hypotenuse?

Answer 14

Opposite!

Answer 15

in the numerator! :D

Answer 16

Yes very good!
Because we're in the 4th quadrant right?
Here's a quick tip to remember: The hypotenuse will never be the negative value.

Answer 17

Woops I wrote \(\large \theta\) for the angle, but it's suppose to be \(\large \beta\).
I guess that's just out of habit :) lol

Answer 18

Using the Pythagorean Theorem, what do you get for the missing side?

Answer 19

Oh!
Yes thats the symbol i should be using lol

Answer 20

the circle with the dash, i thought it was called beta? :O

Answer 21

\(\large \theta\)=theta
\(\large \beta\)=beta

:o

Answer 22

a2+b2=c2?
c is the hypotenuse?

Answer 23

Maybe your teacher pronounces it funny so you got confused hehe

Answer 24

Ohhh! yes theta then sorry...

Answer 25

Yes, c is the 17.

Answer 26

it's 8!

Answer 27

Maybe?

Answer 28

Ok good.
Now remember, we're in the `4th Quadrant`. So should our 8 be positive, or negative?