Question

9. sin 12° x cos 78° + sin 78° x cos 12° is equal to
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Answer 1

Answer:

1

Step-by-step explanation:

sin 12° * sin 12° + cos 12° * cos 12°

sin 12^2 + cos 12^2

1

Answer 2

Answer:

sin12×cos78+sin78×cos12

sin12×cos78+sin (90-12)×cos (90-78)

sin12×cos78+cos12×sin78

sin (12+78)

sin90 =1