Y`=2sin(π/5-2x)-2sin(7π/15+2x)=0
2* 2sin(-2π/15 -2x)cosπ/3=0
-2six(2π/15+2x)=0
six(2π/15+2x)=0
2π/15+2x=πn
2x=-2π/15+πn
x=-π/15+πn/2
y(-π/15)=cos(π/15+2π/15)+cos(7π/15-2π/15)+3=π/5 +cosπ/3+3≈0,848+0,5+3≈4,348
R(R1+R2)=R1R2
RR1+RR2=R1R2
RR1-R1R2=-RR2
R1=-(RR2/R-R2)
в последнем делении RR2 в числители, а R-R2 полностью в знаменателе. "-" перед дробью
A1
а)1/8*18=9/4=2,25
б)-1/27
в)35+25=60
А2
а)2^-4*2^6*2^12=2^14=16384
б)3^-4*3^5*3*7=3²*7=9*7=63
в)4*5/15=4/3=1 1/3
A3
(1,3*3)*(10^-2*10^-1)=3,9*10^-3=0,0039
0,0039<0,004
A4
(y^-2/4x^-1)³*128x^-3y^5=y^-6*128x^-3y^5/64x^-3=2y^-1=2/y
B1
5^-3*5^10/(1+5^-3)=5^10
A1
а)1/8*18=9/4=2,25
б)-1/27
в)35+25=60
A2
а)3^(-5+8-4)=3^-1=1/3
б)2*4*7^-6*7^5=2*7^0=2*1=2
в)16*3/15=16/5=3,2
A3
(2,1*4)*(10^-1*10^-2)=8,4*10^-3=0,0084
0,0084>0,008
A4
(y^-1/3x^-2)^4*162x^-7y^4=y^-4*162x^-7y^4/81x^-6=2x^-1=2/x
B1
2^-12*2^5/(1*2^-15)=2^8=256
X^4-26x^2+169+8x^2-104+16=0
x^4-18x^2+81=0
(x^2-9)^2=0
((x-3)(x+3))^2=0
x-3=0 x1=3
x+3=0 x2=-3
<span>а) 1+sin a = 2cos²(45°- a/2)
1+sina=2*(1+cos(90-a))/2=1+sina</span>
<span>1+sina=</span><span><span>1+sina
</span>формула cos²a=(1-cos2a)/2
b) 2sin²(45°- a) + sin 2a = 1
2(1-cos(90-2a))/2+sin2a=1-sin2a+sin2a=1
1=1
c) 1 - sin a = 2 sin²(45°- a/2)
1-sina=2(1-cosa)/2=1-sina
1-sina=1-sina
</span>