Question

1. Using your calculator, complete the table below for the function y = cos x. Find the corresponding y- values rounded to the nearest thousandth.
x y

0°
-30°
-60°
-90°
-120°
-150°
-180°
-210°
-240°
-270°
-300°
-330°
-360°





Answer 1

We know that cos(-x) = cos x....
apply cos(90-x) , cos(90+x) etc to get the values ;)

Answer 2

@vikrantg4 , I don't know how to do it

Answer 3

It's difficult to type all the answers here :P

Answer 4

just tell the first 3 so i can get an idea

Answer 5

@vikrantg4

Answer 6

do you have a calculator?

Answer 7

no :S

Answer 8

you could use google
type in the google search window
cos(0 deg)=

Answer 9

ok

Answer 10

i got 1

Answer 11

that is because the cosine of zero degrees is one.

Answer 12

ok, so the first one is1, how do i find these second one?

Answer 13

what should i put?

Answer 14

think about it and try it.

Answer 15

-30 is 0.866025404? right?

Answer 16

I would say cos(-30)= 0.866...
notice this: type in
sqrt(3)/2=

does that number look familiar?

Answer 17

yeah, ok, i realized that if i put '' cos(-30)'' or '' cos(30)'' I get the same number so it doesn't matter if it's negative or positive, right?

Answer 18

notice if you type
cos(-30)=
in google you get 0.15425145
that is because it interprets 30 as being in radians. So be sure to say
cos(-30 deg)=

and you can try cos(-30 deg) and compare it to cos(30 deg)

Answer 19

If you had a calculator, you would have to make sure it was in "degree mode" and not "radian mode"

Answer 20

ok, well thanks a lot

Answer 21

also, the question says rounded to the nearest thousandth.
that means to 3 decimals. Look at the 4th digit to the right of the decimal point. if 5 or bigger round up.

0.866025404 rounds to 0.866

Answer 22

yeah i got that, thanks