which of the following trigonometric functions when express in a single angle is equal to cos (25 degrees-35 degrees)?
a.cos 25 cos 35-sin 25 sin 35
b.cos 25 cos 35+sin 25 sin 35
c.cos 25 sin 35-cos 25 sin 35
d.cos 25 sin 35 + cos 25 sin 35