Simplify the Expression Algebraically $$\sin ( 7 x + 7 y ) + \sin ( 7 x - 7 y )$$

question 22

Multiple Choice

Simplify the expression algebraically.​ $$\sin ( 7 x + 7 y ) + \sin ( 7 x - 7 y )$$ ​

• A) \(\sin \left( 7 x ^ { 2 } + 7 y ^ { 2 } \right)\)
• B) \(2 \sin 7 x\)
• C) \(\sin \left( 7 x ^ { 2 } - 7 y ^ { 2 } \right)\)
• D) \(\sin 7 x \cos 7 y\)
• E) \(2 \sin 7 x \cos 7 y\)