Question

what is the fraction of cos 180 degrees into cos 45 degrees cos(180⁰)×cos(45⁰)​ please answer correctly​

Answer 1

$Cos \: 180° = -1 \\ \\ Cos \: 45° = 0.707$

$(Cos 180° \times Cos 45° ) + (Cos 180° \times Cos 45° ) \\ \\ = ( - 1 \times 0.707) + ( - 1 \times 0.707) \\ \\ = - 0.707 + ( - 0.707) \\ \\ = 0.707 - 0.707 \\ \\ = 0$

Answer 2

Cos 180° = - 1

Cos 45° = 0.707

(Cos180° × Cos45°) +(Cos180° × Cos45°)

= (- 1 × 0.707) + (- 1 × 0.707)

= - 0.707 + (- 0.707)

= 0.707 - 0.707

= 0