Question

How would you find the exact value of tan pi/8

Answer 1

so tan(3.14/8?

Answer 2

in previous lessons i learned that you can use sum or difference identities... for ex: cos15= cos(45-30)

and yes @bubbles98

Answer 3

there's the half-angle identity as well

Answer 4

pi/8 is the same thing as 15 degrees

Answer 5

so tan(45-30)

Answer 6

so is what i did is i punch it in the calculator and gor 0.006850524

Answer 7

got*

Answer 8

and use difference formula for tan

Answer 9

@bubbles98 that's not the exact answer

Answer 10

http://www.clarku.edu/~djoyce/trig/tangentformulas.jpg

We'll need the third formula

Answer 11

of course not just a little step so far

Answer 12

i thought pi/8 equals 22.5 degrees.

Answer 13

my bad

Answer 14

you'd have to use the half angle formula then

Answer 15

http://www.freemathhelp.com/images/halfangles.png

3rd one

Answer 16

pi/8 is the same thing as (pi/4)/2 right?

Answer 17

so tan pi/8/2

Answer 18

so... tan(45/2) = sin(45)/(1+cos(45)

Answer 19

no, it'd be tan(pi/4/2)

Answer 20

please keep in mind that:
\[1=\tan(\pi/4)=\frac{ 2 \tan(\pi/8) }{ 1-(\tan(\pi/8))^{2} }\]

Answer 21

I used this identity:
\[\tan(2x)=\frac{ 2 \tan(x) }{ 1-(\tan(x))^{2} }\]