Question

Tolong sama caranya :)

Answer 1

Jawaban:

B. -1

Penjelasan dengan langkah-langkah:

cos²a-sin²a= cos 2a

cos³(5 pi/2)-sin²(5 pi/2)= cos (2(5 pi/2))

= cos 5pi

= cos 900°

= cos (2 × 360° + 180°)

= cos 180°

= cos (180°-0)

= -cos 0°

= -1