Question

sin37°sin23°- cos37°cos23°
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Answer 1

Answer:

-cos(37+23)

-cos 60

-1/2

Answer 2

Answer:

Step-by-step explanation:

2SinASinB=Cos(A-B)-Cos(A+B)

2CosACosB=Cos(A+B)+Cos(A-B)

Subtracting above 2 we get

2(SinASinB-CosACosB)=-2Cos(A+B)

Here A=37

B=23

Sin37Sin23-Cos37Cos23=(-)Cos(37+23)

Sin37Sin23-Cos37Cos23=(-)Cos(60)

Sin37Sin23-Cos37Cos23=(-)1/2