jika p= sin alpha+cos alpha dan q=cos alpha-sin alpha maka p^2+q^2=...

p = sin α + cos α
q = cos α - sin α

p² + q²
= (sin α + cos α)² + (cos α - sin α)²
= sin² α + 2 sinα.cosα + cos²α + cos²α - 2 sinα.cosα + sin²α
= sin²α + cos²α + cos²α + sin²α
= 2 sin² α + 2 cos²α
= 2(sin²α + cos²α)
= 2 ( 1 )
= 2