Question

Can somebody explain to me how to do this please?

cos(arctan 3/4)

Answer 1

gladly!
it's saying what angles have a tan=3/4 ?
tan is opp/adj
opposite=3
adjacent=4
that means hypotenuse=5
cos is adjacent/hypotenuse
knowing both adjacent and hypotenuse, cos of the angle that has a tan=3/4 would be cos(4/5) which is equal to what?

Answer 2

@ijakez you're on the right track, but you made an error when you got to `cos(4/5)`

Answer 3

the angle theta that has a tangent tan(theta)=3/4
that angle would have a cos(theta)=4/5
arccos(4/5)=?
oopsies!

Answer 4

The following wording might make more sense to you and others:

Instead of "knowing both adjacent and hypotenuse, cos of the angle that has a tan=3/4 would be cos(4/5) which is equal to what?"

"The cosine of the angle that has a tangent of 3/4 would be adj/hyp (as usual), which in this case comes out to 4/5." (Not cos (4/5).

You could also do this: "Let x be the angle in question. Then tan x = 3/4 and cos x = 4/5."

Answer 5

yeah my mistake