Question

9. (cos 0° + cos 45º+sin 30)(sin 90° - cos 45º + cos 60°)​

Answer 1

Step-by-step explanation:

(cos 0° + cos 45° + sin 30°)(sin 90° - cos 45° + cos 60°)

=> (1 + 1/√2 + 1/2)(1 - 1/√2 + 1/2)

=> (1+1/2+1/√2)(1+1/2-1/√2)

=> (3/2 + 1/√2)(3/2 - 1/√2)

=> (3/2)² - (1/√2)²

=> 9/4 - 1/2

=> (9 - 2) / 4

=> 7/4