- #1

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## Homework Statement

Without using tables(calculators) find the numerical value of

Sin[Pi/8]^2 - Cos[3 (Pi/8)]^4

## Homework Equations

## The Attempt at a Solution

I tried changing it to:

1-cos[pi/8]^2 - cos[3pi/8]^4 but have no idea where to go... its really got me scratching my head.

Any ideas? Any help is much appreciated, thank you.