У=5lgx/3;x>0
y/5=lgx/3
x/3=10^(y/5)
x=3*10^(y/5)
обрат.функц.
Y=3*10^(x/5)
1.
1)sin765=sin(720+45)=sin45=√2/2
2)cos19π/6=cos(3π+π/6)=cos(π+π/6)=-cosπ/6=-√3/2
2.
cosa=-√1-0,09=-√0,91=-0,1√91
3.
1)cosacosb+sinasinb-cosacosb+sinasinb=2sinasinb
2)(-sina-cosa)/(-2cosacosa+1)=-(sina+cosa)/(-2cos²a+sin²a+cos²a)=-(sina+cosa)/(sin²a-cos²a)=-(sina+cos)/(sina-cosa)(sina+cosa)=-1/(sina-cosa)=1/(cosa-sina)
4.sinxcos3x+cosxsin3x=-1
sin(x+3x)=-1
sin4x=-1
4x=-π/2+2πn
x=-π/8+πn/2
5.((sina/cosa+cosa/sina)*(cos²2a+sin²2a-cos²2a+sin²2a)= ((sin²a+cos²a)/sinacosa)*2sin²2a=2/sin2a*2sin²2a=4sin2a
-3/2+6/11×22/3-2×2
-3/2+2×2-4
-3/2+4-4
-3/2
1)X1=-3 во 2 (дробь) x2=1
2)(a+4) × 2a 2a
--------------------- = -------------
(a-4)×(a+4) a-4
Так вроде
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