Returning trigonometric value answers in irrational form

Question

I need to find the irrational form of Sin[7*\[Pi]/8]. But in Mathematica, I can get its numerical value. I am getting

Sin[\[Pi]/4]=1/Sqrt[2]

in Mathematica. What I meant is an answer something like this for Sin[7*\[Pi]/8] as well. Is that possible?

it is hard to understand what you are asking. But if you mean you want Mathematica not to automatically write Sin[Pi/4] as 1/Sqrt[2], you can check this answer prevent-simplification-of-trig-functions — Nasser, Jun 21 '21 at 02:30

score 6 · Accepted Answer · answered Jun 21 '21 at 03:20

6

The following does the job.

Sin[7*\[Pi]/8] // ToRadicals

Sqrt[2 - Sqrt[2]]/2

answered Jun 21 '21 at 03:20

user64494

1 Answers1