Представьте в виде произведения

sin40+sin16

sin20-sin40

cos46-cos74

cos15+cos45

sin2P/5+sinP/5

Sin40+sin16=2sin28cos12

2. - 2sin10cos30

3. cos46-cos74=2sin14sin60

4. cos15+cos45=2cos30cos15

5. sin2π/5+sinπ/5=2sin3π/10cos π/10

6. cos11π/12+cos9π/12=2cos10π/12cosπ/12

7. cos (π/3-a) + cosa=2cosπ/6*cos (π/6-a) = 2

8. sin (π/6+a) - sin (π/6-a) = 2sina*cosπ/6