Math
posted by Shannon on .
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°

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"