Объяснение:
1. =52⋅2⋅52⋅cos60°=52⋅2⋅52⋅1/2=
2. =52⋅52⋅cos60°=52×52×1/2
3. =52⋅52⋅cos120°=52⋅52⋅(−1/2)=
Объяснение:
1. =52⋅2⋅52⋅cos60°=52⋅2⋅52⋅1/2=
2. =52⋅52⋅cos60°=52×52×1/2
3. =52⋅52⋅cos120°=52⋅52⋅(−1/2)=