Задача 50427 1) cos58°cos32°–sin58°cos32° 2)...

251ls1

2020-05-16 20:03:53

1) cos58°cos32°–sin58°cos32°
2) sin45°cos45°+cos45°sin45°
3) cos12°cos33°–sin12°sin33°
4)sin15°cos45°+cos15°sin45°

vk397114329

2020-05-16 22:37:58

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4) sin15*cos45*+cos15*sin45*=sin45*(sin15*+cos15*)=
=sin45*(sin15*+sin75*)=sin45*(2sin45*cos60*)=
=sgrt(2)/2*2*sgrt(2)/2*(1/2)=0.5
3) cos12*cos33*-sin12*sin33*=
=cos(33*+12*)=cos45*=sgrt(2)/2
2) sin45*cos45*+cos45*sin45*=
=sin90*=1
1) Решается аналогично.