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The value of \(\sin 20° \cos 70° + \cos 20° \sin 70°\) is:

  • A.0
  • B.1
  • C.1/2
  • D.√3/2

Answer: B

This expression is in the form of the sine addition formula: \(\sin(A+B) = \sin A \cos B + \cos A \sin B\).

Here, A = 20° and B = 70°.

The expression is equal to \(\sin(20° + 70°) = \sin(90°)\).

The value of \(\sin 90°\) is 1.

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