How do you evaluate #1-2cos^2(pi/8)#?
1 Answer
Dec 12, 2016
Explanation:
Call
Replace cos^2 t by (1 - sin^2 t), we get:
Use trig identity:
There for:
Check by calculator.
Call
Replace cos^2 t by (1 - sin^2 t), we get:
Use trig identity:
There for:
Check by calculator.