Odpowiedzi

2010-02-01T20:15:32+01:00
(cos a +sin a )²- (cos a - sin a )²=4sin a cos a
(cos²α+2sinαcosα+sin²α)-(cos²α-2sinαcosα+sin²α)=4sinαcosα
1+2sinαcosα-(1-2sinαcosα)=4sinαcosα
1+2sinαcosα-1+2sinαcosα=4sinαcosα
4sinαcosα=4sinαcosα
L=P