SOLUTION: Write the expression as the sine, cosine, or tangent of an angle.
cos 112° cos 45° + sin 112° sin 45°
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-> SOLUTION: Write the expression as the sine, cosine, or tangent of an angle.
cos 112° cos 45° + sin 112° sin 45°
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Question 1018132: Write the expression as the sine, cosine, or tangent of an angle.
cos 112° cos 45° + sin 112° sin 45° Found 2 solutions by ikleyn, MathTherapy:Answer by ikleyn(52803) (Show Source):
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Write the expression as the sine, cosine, or tangent of an angle.
cos 112° cos 45° + sin 112° sin 45°
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1.
cos(112°)*cos(45°) + sin(112°)*sin(45°) = cos(112°)*cos(-45°) - sin(112°)*sin(-45°) =
Apply the formula for cos of the sum of angles for 112° and -45°
See the lesson Addition and subtraction formulas in this site.
= cos(112° - 45°) = cos(67°).
2.
Of which angle?
