Question

1)(sina+cosa)^2 +(sina -cosa)^2-22) (cosa+sina)^2 -(cosa+sina)^2+cosa*sinaДокажите тождество1-sin^2 a 1________= ______1-cos^2 a tg^2aa-альфа

Answer 1

1)(sina+cosa)^2 +(sina -cosa)^2-2=sin^2+2sinacosa+cos^2a+sin^2a-2sinacosa+cos^2a-2=1+1-2=0

2) (cosa+sina)^2 -(cosa+sina)^2+cosa*sina=cos^2a+2cosasina+sin^2a-cos^2a+2sinacosa-sin^2a+cosasina=5cosasina

1-sin^2 a         cos^2a        ctg ^2  a                1

________=  ______  =                        = --------------------

 

1-cos^2 a      sin^2a                                       tg ^2 a