Cos(-7,9π)*tq(-1,1π) -sin5,6π*ctq4,4π =cos7,9π*(-tq1,1π) - sin5,6π*ctq4,4π =
- cos(8π - 0,1π)*tq(π+0,1π) - sin(6π-0,4π)*ctq(4π+0,4π) =
- cos0,1π)*tq0,1π - (-sin0,4π)*ctq0,4π) = -sin0,1π +cos0,4π=
-sin(0,5π -0,4π) +cos0,4π = - cos0,4π +cos0,4π =0.
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* * * sin0,1π = sin(0,5π -0,4π) =sin(π.2 -0,4π) =cos0,4π * * *
ответ : 0.
1) 4(13-3x)-17=-5x
52-12x-17=-5x
-12x+5x=17-52
-7x=-35
x=-35/-7
x=5
2) (18-3x)-(4+2x)=10
18-3x-4-2x=10
-3x-2x=10+4-18
-5x=-4
x=-4/-5
x=0.8
√2(√18-√2)=√(2*18)-√(2*2)=√36-√4=6-2=4.
3х*8=13-18х
24х+18х=13
42х=13
х=13/42