Question

Exact value of :
cot(15 degrees)
sin(195 degrees)
cos(7pi/12)
Only fractions and radicals. No decimals.

Answer 1

@divu.mkr

Answer 2

@mathslover

Answer 3

@CGGURUMANJUNATH

Answer 4

Hint: 15=45-30, 195=180+15, 7pi/12=pi/2+pi/12

Answer 5

okayy

Answer 6

@CGGURUMANJUNATH

Answer 7

Yeah, go on calling people to help you

Answer 8

Keep being lazy by not using your brain

Answer 9

ha you don't even know half of the work I do

Answer 10

I've got a 4.5 gpa just that trig isn't my strong point and you know what I'm kinda tired its the end of the week

Answer 11

Formulas that will be useful:
\[\sin(A\pm B)=\sin A\cos B\pm\cos A\sin B\]\[\cos(A\pm B)=\cos A\cos B\mp\sin A\sin B\]\[\tan(A\pm B)=\frac{\tan A\pm\tan B}{1\mp\tan A\tan B}\]

Answer 12

thank you I already have them but don't understand how to apply them

Answer 13

what would be A? B?

Answer 14

A and B can be anything you like, and the equality still stands.

Answer 15

For example you can put A=45deg and B=30deg to the first one, you'll get:
\[\sin(45^\circ+30^\circ)=\sin45^\circ\cos30^\circ+\cos45^\circ\sin30^\circ\]

Answer 16

Simplify that and you'll get \(\displaystyle\sin(75^\circ)=\frac1{\sqrt2}\cdot\frac{\sqrt3}2+\frac1{\sqrt2}\cdot\frac12\)

Answer 17

Simplify that further and you'll have the value of \(\sin75^\circ\), get it?

Answer 18

great

Answer 19

Yes or no

Answer 20

You have to give me response or I can't help you

Answer 21

yeah

Answer 22

Good, now find the value of \(\tan15^\circ\) by using the formula

Answer 23

okayy well I already got the answers to all of them could you check them?

Answer 24

Okay

Answer 25

What are your answers?

Answer 26

cot 15 = 2 + radical 3
sin 195 = - (radical 3 - 1) / 2 radical2
cos 7pi/12 = -(radical 3 - 1) / 2 radical2

Answer 27

All correct

Answer 28

Awesome thanks!