(sin5L-sinL)/(2cos3L)

Question

(sin5L-sinL)/(2cos3L)

Comments

Что сделать?

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сократить

Answer 1

=2sin((5l-l)/2)cos((5l+l)/2)/2cos(3l)=
2sin(2l)cos(3l)/2cos(3l)=sin(2l)