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The expression sin 25° cos 47° + cos 25° sin 47° is equivalent to
(1) sin 22° (2)sin 81° (3) cos 22° (4) cos 81°

  • Math -

    recall that
    sin(A+B) = sinAcosB + cosAsinB

    we have the pattern of the right side of that equation
    sin 25° cos 47° + cos 25° sin 47°
    = sin(25+47) = sin 72° or cos 18° by the complimentary angle property

    which does not match any of your choices, so
    "none of these"

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