Question

Trig: Can someone answer these questions real quick then explain them? I have to have them turned in in 20 mins! http://prntscr.com/433gw2

Answer 1

also: http://prntscr.com/433ixs

Answer 2

for question 3
\[\sin(a-b) = \sin a \cos b - \sin b \cos a\]

question 4:
\[\tan \frac{x}{2} = \frac{1-\cos x}{\sin x}\]

Answer 3

for general reference:
http://en.wikipedia.org/wiki/Trig_Identity

Answer 4

Can you please answer them? I got #3 but #4 is confusing me with the into you supplied

Answer 5

I will be happy to fan, medal and everything else if you just answer them real quick

Answer 6

question 1:
\[\cos \frac{19\pi}{12} = \cos (\pi + \frac{7\pi}{12}) = -\cos \frac{7\pi}{12}\]
then use half angle formula for cos

Answer 7

ok for #4

x/2 = 15 so x =30
what is cos30? sin30?
plug them into identity

Answer 8

Don't understand #1, #2, or #5

Answer 9

question 2:
\[\cos(165) = \cos(120+45)\]
\[= \cos 120 \cos 45 - \sin 120 \sin 45\]

Answer 10

just use that?

Answer 11

5 mins for1 and 2!

Answer 12

question 5 is just like question 3 except you are adding
\[\rightarrow \sin (\frac{\pi}{2}+\frac{\pi}{7})\]

Answer 13

9π/14?

Answer 14

haha dont wait til the last minute, im helping as fast as i can

Answer 15

yes ^

Answer 16

lol, sorry, I've been working for 5 hours on this

Answer 17

Ok just one!

Answer 18

We can do it!!!

Answer 19

use the half angle formula from the wiki page

Answer 20

0.99811698

Answer 21

\[\cos \frac{x}{2} = \sqrt{\frac{1+\cos x}{2}}\]

Answer 22

you need exact value not decimal

Answer 23

What is it? I have the decimal but I can't get it the exact value

Answer 24

Thanks for all of the help! Just gotta get through this last one!

Answer 25

\[-\frac{\sqrt{2-\sqrt{3}}}{2}\]
this is what i get

Answer 26

That's not even one of the answers!

Answer 27

It's close to one, let me see if it's the right answer... I have to turn this in now!

Answer 28

It's not the right answer and is not close to the correct answer! Thanks for all the help! YOUR GREAT

Answer 29

for a cow...

Answer 30

its the first option

Answer 31

damn.