Question

find the value of tan 5π/8

Answer 1

well; we can either try to se trig formulas; or simply use a calculator

Answer 2

http://www.wolframalpha.com/input/?i=tan%285pi%2F8%29

Answer 3

oh, sorry. no calculators, says to use trig functions.

Answer 4

you wanna use either a tan(a+b) or a tan(a-b) formula than; and find 2 angles that either add to or subtract to 5pi/8

Answer 5

nice website, thanks

Answer 6

tana+tanb
tan(a+b) = -------------
1- tana.tanb



tana-tanb
tan(a-b) = -------------
1+ tana.tanb

Answer 7

tan(2a) = 2.tana
---------
1-tan^2(a)

Answer 8

but i dont see that one being helpful :)

Answer 9

i dont se any of the familiar angles summing it up to get 112.5

Answer 10

it is 225 degrees/2 tho; so maybe split that tan into sin and cos functions and work on half angle formulas

Answer 11

either way you go, its gonna be a nightmare

Answer 12

i know, but it looks like it would be so easy!

Answer 13

thanks for trying

Answer 14

it might be; but youd have to do allllooooottt of typing; and its just not that fun to try to keep track of on a keyboard

Answer 15

sqrt(1+cos(5pi/4))
----------------- = tan(5pi/8)
sqrt(1-cos(5pi/4))

Answer 16

sqrt(1+[-1/sqrt(2)])
-------------------
sqrt(1 - [1/sqrt(2)])

Answer 17

\[\sqrt{\frac{\sqrt{2}-1}{\sqrt{2}+1}}\]

Answer 18

thats the exact form

Answer 19

well; i think it finally settles down to: -1 - sqrt(2)