Question

how do you find the exact value of
tan^-1(tan4pi/5)

Answer 1

Let\[\theta =\tan [(4\pi)/5]\]Draw a triangle with theta. From the triangle find tan inverse of theta.

Answer 2

wat happened to tan^-1

Answer 3

Nothing happened. All problems have steps. From the triangle find tan^-1 of theta.

Answer 4

i got pi/5 yet the answer (-pi/5)

Answer 5

I don't know what you did.

Answer 6

did u get (-pi/4)?

Answer 7

sorry 5?

Answer 8

I would think you would get some numbers representing sides of triangles.

Answer 9

nah answer is (-pi/4)

Answer 10

* (-pi/5)

Answer 11

Don't concentrate on the answer. Use the answer as a check. Concentrate on the work.

Answer 12

ye i cant seehow they got the answer thought

Answer 13

Usually you are given a special angle to work with. 4pi/5 is not a special angle, I don't think, did you copy the question right?

Answer 14

yep

Answer 15

Go back to what I said earlier. Actually let 4pi/5=theta. Draw a triangle with theta as I labelled it. Call the side opposite theta x and the adj 1. Therefore tan of theta is x/1.
It follows tan^-1 theta is 1/x. Theta is the angle whose tan is 1/x. I think they flipped it to 5pi/4, which after inspection should be same angle as -pi/5. Got to go, don't have time to check my thesis.

Answer 16

k thanks

Answer 17

tan inverse and tan are inverse functions
they cancel each other
and you should get 4pi/5
but how do we get -pi/5 let me think ...

Answer 18

what is the restriction on the domain of tan inverse

Answer 19

the domain is -pi/2 to pi/2
4pi/5 is definity not between this

Answer 20

tan4pi/5=tan(-pi/5)
4pi/5 is over there in the cooridate (-,+)
and -pi/5 is over ther ein the coodinate (+,-)
and -pi/5 is in between -pi/2 and pi/2
so tan^(-1)(tan(-pi/5))=-pi/5

Answer 21

and you there?

Answer 22

thanks man