4√а + 3√а - 2√а = √а( 4 + 3 - 2 ) = 5√а
Sin57cos27+cos57sin27= sin(57 + 27) = sin(84) ≈ 0.99
sin57cos27-cos57sin27= sin(57 - 27) = sin(30) = 1/2
2sin 75*cos75= sin2*75 = sin150 = sin(180 - 30) = sin30 = 1/2
2sin 75 - cos75 = 2si + 45) – cos(30 + 45) = 2sin30cos45 + 2cos30sin45 – cos30cos45 + sin30sin45 = 2*(1/2)*(√2/2) + 2*(√3/2)*(√2/2) - (√3/2)*(√2/2) + (1/2)* (√2/2) = 3√2/4<span> - √6/4</span>
Y=kx+3;
A(5;8)⇒
уравнение прямой ,проходящей через точку А:
y-8=k(x-5);⇒y=k(x-5)+8;y=kx-5k+8;
kx+3=k(x-5)+8;
kx-kx+5k=8-3;
5k=5;k=1;