Question

Let cos p=.22 What is cos p/2?

Answer 1

cos 2p = 2cos^2 p - 1
can you proceed now ?

Answer 2

No

Answer 3

Use this formula, then:
\[\Large \cos\left(\frac{p}2\right)=\sqrt{\frac{1+\cos(p)}{2}}\]

Answer 4

.78 is that right

Answer 5

Approximately, yes.

Answer 6

Thank you can i put up another one not sure but I think my answer is wrong on another question

Answer 7

Okay, go ahead.

Answer 8

sin m=.11 what is sin m/2 I got 0.055 but seems to easy that way?

Answer 9

First, you need to get cos m

Answer 10

I don't know how to ?

Answer 11

Well, you can always use this formula...
\[\Large \cos^2 m + \sin^2 m =1\]

Answer 12

Is .78 the answer for this to?

Answer 13

Let's find out.
First, find cos m using that formula I posted...

Answer 14

I got .78 ? for cos 2 not right is it

Answer 15

mean cos m

Answer 16

What formula have you been taught for half-angle of sine?

Answer 17

that my problem not been given one been looking all online for help feel like we a skipping sections in class

Answer 18

Okay, when you are given the sine, to get the cosine, use this formula:
\[\Large \cos(m) = \sqrt{1-\sin^2m}\]

Answer 19

.883176087 ?

Answer 20

nope

Answer 21

.223606798

Answer 22

Please don't guess :)
What is sin m?

Answer 23

.11 then i divided by 2

Answer 24

No, just sin m for now, not cos m

Answer 25

0.055 and put in equation you gave

Answer 26

not sure

Answer 27

sin m is 0.11, yes?

Answer 28

0.88

Answer 29

No, sin m... it's 0.11

Answer 30

If you have the sine, to get the cosine, use this formula (altered so you can better understand)
\[\Large \cos(m) = \sqrt{1-[\sin(m)]^2}\]

Answer 31

answer is .78