Б) 3sin(3B+5B)*cos(3B-5B)=3sin(8B/2)*cos(-2B/2)=2sin4B*cosB
Sin112cos22-sin22cos112=sin(112-22)=sin90=1
Y=-3*(-1.5)*1.5=6.75
y=-3*2.5*1.5=-11.25
y=-3*4*1.5=-18
Tga/2=6/5
cos²a/2=1:(1+tg²a/2)=1:(1+36/25)=25/61
cosa/2=5/√61
cosa=2cos²a/2-1=2*25/61-1=50/61-1=-11/61
sina/2=√(1-cos²a/2)=√(1-25/61)=6/√61
sina=2sina/2cosa/2=2*6/√61*5/√61=60/61
tga=sina/cosa=60/61:(-11/61)=-60/11
ctga=1/tga=-11/60
1. 1/(6х-4у)-1/(6х+4у)-3х/(4у²-9х)=1/2(3х-2у)- 1/2(3х+2у)+ 3х/(3х-2у)(3х+2у)=числитель 3х+2у-(3х-2у)+6х/знаменатель 2(3х-2у)(3х+2у)=числитель 3х+2у-3х+2у+6х/ знамен 2(3х-2у)(3х+2у)=числитель 2(3х+2у)/знам 2(3х-2у)(3х+2у)=1/(3х-2у)............