7.у=cos²x+3=(1+cos2x)/2+3=3.5+0.5cos2x
Т=2π/2=π, ответ В)
8. у=2cos2x+(1-cos2x)/2=2cos2x+1/2-((cos2x)/2)=1.5cos2x+0.5
-1≤cos2x≤1; -1.5≤1.5cos2x≤1.5; -1.5+0.5≤0.5+1.5cos2x≤0.5+1.5; -1≤0.5+1.5cos2x≤2; наибольшее значение равно двум.
9. у=4sinxcosx+3=2sin2x+3
у(0)=4(sin0)*(cos0)+3=3
у(π/12)=2(sin2*π/12)+3=2*0.5+3=1+3=4
у(π/4)=2(sinπ/2)+3=2*1+3=5
у(0)+у(π/12)+у(π/4)=3+4+5=12
7.у=cos²x+3=(1+cos2x)/2+3=3.5+0.5cos2x
Т=2π/2=π, ответ В)
8. у=2cos2x+(1-cos2x)/2=2cos2x+1/2-((cos2x)/2)=1.5cos2x+0.5
-1≤cos2x≤1; -1.5≤1.5cos2x≤1.5; -1.5+0.5≤0.5+1.5cos2x≤0.5+1.5; -1≤0.5+1.5cos2x≤2; наибольшее значение равно двум.
9. у=4sinxcosx+3=2sin2x+3
у(0)=4(sin0)*(cos0)+3=3
у(π/12)=2(sin2*π/12)+3=2*0.5+3=1+3=4
у(π/4)=2(sinπ/2)+3=2*1+3=5
у(0)+у(π/12)+у(π/4)=3+4+5=12