Use a half-angle identity to find the exact solution of cos(3pi/8).

If , then .

Recall the double angle identity,

so we have

pakistan's principal natural resources are arable land and water. about 25% of pakistan's agriculture accounts for about 21% [1] of gdp and employs about 43% of the labour force. in pakistan, the most agricultural province is punjab where wheat and cotton are the most grown.