Question

Find the radian measures of the angles whose sine is –0.8. Round to the nearest hundredth.

–0.93 + 2πn and 4.07 + 2πn

–0.93 + 2πn and 5.36 + πn

–0.93 + 2πn and 5.36 + 2πn

–0.93 + 2πn and 2.21 + 2πn
a?

Answer 1

@robtobey

Answer 2

@agent0smith

Answer 3

whats the question?

Answer 4

I fixed it

Answer 5

@agent0smith do you know

Answer 6

@Mehek14

Answer 7

@TheSmartOne

Answer 8

@sweetburger

Answer 9

@Mehek14

Answer 10

@jhonyy9

Answer 11

@Luigi0210

Answer 12

@paki

Answer 13

@perl

Answer 14

@perl

Answer 15

You need to solve the equation sin x = -.8

Answer 16

how would i do that?

Answer 17

We can take the inverse sine of both sides.

sin^-1 ( sin ( x ) ) = sin^-1( -.8)

Answer 18

ok so how would i plug thAT into my calc

Answer 19

sin^-1 ( sin ( x ) ) = sin^-1( -.8)
x = sin^-1( -.8)
x = -.927295

Answer 20

You can add a multiple of 2pi to this to get coterminal angles.

Answer 21

ok now what would i do

Answer 22

To get the other angle, make use of this identity
\( \color{red}{\ sin( \pi - x ) = \sin x }\)

Then solve.
\( \sin(\pi-x) = -.8 \)
\( \pi - x= \sin^{-1}(-.8) \)

solve for x
\( x = \pi - \sin^{-1}(-.8) \)

Answer 23

Do you have a scientific calculator?

Answer 24

no

Answer 25

@perl

Answer 26

@perl

Answer 27

I think google has a scientific calculator.

Answer 28

it wont let me type in "x"

Answer 29

@perl

Answer 30

http://www.wolframalpha.com/input/?i=pi+-+arcsin(-.8)

Answer 31

i got 4.07 @perl

Answer 32

@perl

Answer 33

That is correct.