1. 50 + 3 * ( 2x - 1 ) = 71
50 + 6x - 3 = 71
6x = 71 - 50 + 3
6x = 24
x = 4
24
(ctg²2a-1)/2ctg2a -cos8a*ctg4a=ctg4a-cos8a*ctg4a=
=ctg4a*(1-cos8a)=cos4a/sin4a *2sin²4a=2sin4a8cos4a=sin8a
25
(sin^4a-cos^4a+cos²a)/2(1-cosa)=
=[(sin²a+cos²a)(sin²a-cos²a)+cos²a]/2(1-cosa)=
=(sin²a-cos²a+cos²a)/2(1-cosa)=sin²a/2(1-cosa)=
(1-cos²a)/2(1-cosa)=(1-cosa)(1+cosa)/2(1-cosa)=(1+cosa)/2=
=2cos²(a/2)/2=cos²(a/2)
Х= -1.4 У=-4.7 ; Х=2.6 У=-2.7 ; Х=8.8 У=0.4 У=-3.4 Х= 2.8 ; У=-1.8 Х=4.4; У=2.4 Х=12.8
(3ⁿ⁻¹)²=3²ⁿ⁻²=81
3²ⁿ⁻²=3⁴
2n-2=4
2n=6
n=3
(10²)⁽ⁿ⁻¹⁾=100⁽ⁿ⁻¹⁾=10000
100⁽ⁿ⁻¹⁾=100²
n-1=2
n=3
8x^2 - 16x + 7 = 0
D = (-16)^2 - 4*8*7 = 256 - 224 = 32
√D = √(16*2) = 4√2
x1 = ( 16 + 4√2)/16 = (4 + √2)/4
x2 = ( 4 - √2)/4 = 1 - √2/4
Ответ:
x = 1 ± √2/4