1
sin²a=(1-cos2a)/2=(1-1/3):2=2/3:2=1/3⇒sina=1/√3
cos²a=(1+cos2a)/2=(1+1/3):2=4/3:2=√2/√3
tga=1/√3:√2/√3=1/√3*√3/√2=1/√2
tg(a+π/4=(tga+tgπ/4)/(1-tgatgπ/4)=(1/√2+1):(1-1/√2)=(1+√2)/(√2-1)=
=(1+√2)²/(2-1)=3+2√3
2
y=4sinxcosx-1=2sin2x-1
E(x)=2*[-1;1]-1=[-2;2]-1=[-3;1]
y=-3 наим у=1-наиб
3
cosx(2sinx-1)<0<br>1)cosx<0 U sinx>1/2⇒x∈(π/2+2πn;5π/6+2πn,n∈z)
2)cosx>0 U sinx<1/2⇒x∈(-π/2+2πk;π/6+2πk,k∈z)