Question

Use half angle identities to find exact value:
tan Ө

Answer 1

Ө=22.5 degrees

Answer 2

@Hero

Answer 3

got sin and cosӨ, just stuck on tanӨ :O

Answer 4

I'm kinda busy. Ask @hartnn

Answer 5

@everyone!

Answer 6

hint

22.5*2 = 45

Answer 7

now use tan 2 theta formula :)

Answer 8

\[\large \tan 2 \theta=\dfrac{2\tan \theta}{1+\tan^2 \theta}\]

Answer 9

you will get a quadratic in tan theta

Answer 10

oops its 1-tan^2

Answer 11

isn't that double angle formula ?

Answer 12

i want half angle :P

Answer 13

I think this is enough ..you get a quadratic

Answer 14

I agree. There should be an @everyone ping

Answer 15

lol

Answer 16

umm but i want to see it in half angle!

Answer 17

well..more like i need to see it in half angle lol

Answer 18

theta =2ttheta/2

Answer 19

infact I applied half angle here took 22.5 as half angle for 45

Answer 20

\(\large \tan \theta=\dfrac{2\tan (\theta/2)}{1+\tan^2 (\theta/2)}\)

Answer 21

1-tan^2 theta/2 ?

Answer 22

hold on..this is not the way i learn in class :|

Answer 23

yeah, 1- ...

Answer 24

:)

Answer 25

what about cos or sin ?

Answer 26

you can use formula for cos 2 theta and sin 2 theta similarly

Answer 27

infact once you get any of the above you can use tan theta to get value of other

Answer 28

and then divide by 2 ?

Answer 29

use formula for cos2theta and sin2theta and divide by 2 ? to get half angle?

Answer 30

sin2θ = 2cosθsinθ

Answer 31

oops i think i made a mistake on that

Answer 32

use this then

1+cos 2 theta =2cos ^2 theta

Answer 33

here 2 theta =45

Answer 34

theta =2.5

Answer 35

*22.5