# Write the expression as the sine, cosine, or tangent of an angle.

sin57° cos13° - cos57° sin13°. Select one:

cos70°

cos44°

sin44°

sin70°

**Solution: **

Given: Expression is sin57° cos13° - cos57° sin13°

This shows the difference of two angles 57° and 13°.

sin(a - b) = sina cosb - cosa sinb is the most applied trigonometric formula.

So here we have a = 57° and b = 13°

sin57° cos13° - cos57° sin13° = sin(57° - 13°)

⇒ sin57° cos13° - cos57° sin13° = sin44°

## Write the expression as the sine, cosine, or tangent of an angle.

sin57° cos13° - cos57° sin13°. Select one:

**Summary: **

The value of sin57° cos13° - cos57° sin13° is sin44°.