а) = 5/8= 0,625;
б) = √784 = 28:
в) = 4√3 : 3* 2/3 + 0,5= 4√3 : 2 + 0,5= 2√3+0,5
Sin(a+b) = Sina*Cosb + Sinb*Cosa
<span>Sin14*Cos46 + Sin46*Cos14 = Sin(14+46) = Sin60 = </span>√3/2 C
Sin(x-y)=sinxcosy-cosxsiny
sin7xcos3x-cos7xsin3x=-1
sin(7x-3x)=-1
sin4x=-1
4x=3pí/2+2k.pí
x=3pí(8+k.pí/2, k=0,1,-1,2,-2,.....