Sederhanakan bentuk ekspresi ( sinB + cosB)^2 + ( sinB – cosB )^2

(sinB + cosB)² + (sinB – cosB)² =
sin²B + cos²B + 2sinBcosB + sin²B + cos²B – 2sinBcosB
2(sin²B + cos²B)
Ingat! sin²B + cos²B = 1
2(1) = 2