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please help me please

[tex]2 \sin7 \alpha .cos2 \alpha = sin9 \alpha + sin5 \alpha [/tex]
it's a prove that​


Answer :

Answer:

they are identical. proved below.

Step-by-step explanation:

  • formula:  [tex]sin(t)+sin(s) = 2sin(\frac{t+s}{2} )cos(\frac{t-s}{2} )[/tex]

using the formula to proof:

[tex]sin9a+sin5a[/tex]

[tex]2sin(\frac{9+5}{2})* cos(\frac{9-5}{2})[/tex]

[tex]2sin7a * cos2a[/tex]

True. proved that they are identical.