Answer: cos (25° + 10°)
Step-by-step explanation: The expression:
sin(25°) cos(10°) − cos(25°) sin(10°)
is associated to the expression for the cosine of the sum of two angles that is:
cos (α+β) = sinα *cosβ -cosα*sinβ
Hence if we do α = 25° and β = 10°
by subtitution we get:
cos (25° + 10°) = sin(25°) cos(10°) − cos(25°) sin(10°)
