Circular Trigonometry Question

Question

Match the appropriate formula that would result in an exact value.

cos 45° = Answer

sin 195° = Answer

Formulas: sin (180°+15°) / cos (45°+30°) / sin (225°-30°) / cos (10°+5°) / sin (100°+95°) / cos (315°-270°)

Answer 1

cos 45 = cos (315-270). This works because it would still give you a positive value. (cos is positive in the 1st and 4th quadrants)

sin 195 = sin (225 - 30). This works because sin would still be negative. ( sin is negative in the 3rd quadrant)