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  1. The value of
    sin 43°
    		+
    cos 19°
    		- 8 cos²60° is
    cos 47°sin 71°
    1. 0
    2. 1
    3. 2
    4. - 1
Correct Option: A

Expression

=
sin 43°
+
cos 19°
- 8 cos² 60°
cos 47°sin 71°

=
sin 43°
+
cos 19°
- 8 × (1 / 2)²
cos (90° - 43°)sin (90° - 19°)

=
sin 43°
+
cos 19°
- 8 × (1 / 4)
sin 43°cos 19°

[sin (90° – θ) = cos θ;cos (90° – θ) = sin θ]
= 1 + 1 - 2 = 0


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