Ответы и объяснения

2013-05-16T12:59:10+04:00
1-2sin^2 x = 3/5;
sin^2 x = 1/5
sin x = 1/sqrt(5)
cos x = 2/sqrt(5);
tg x = 0,5
ctg x = 2;
  • Firs
  • хорошист
2013-05-16T13:07:39+04:00

cos2x=cos^2x-sin^2x

sin^2x=1-0.36

sin^2x=0.64

cos2x=(-0.6)^2-0.64=-0.28