![3*10^{-1} +1*10^{-2} +5*10^{-4} =3* \frac{1}{10} +1* \frac{1}{10^{2} }+5* \frac{1}{10 ^{4} } = \\ \frac{3}{10} +1* \frac{1}{100} +5* \frac{1}{10000}= \frac{3}{10}+ \frac{1}{100}+ \frac{1}{2000} = \frac{600}{2000} + \frac{20}{2000}+ \\ \frac{1}{2000}= \frac{621}{2000} =0.3105](https://tex.z-dn.net/?f=3%2A10%5E%7B-1%7D+%2B1%2A10%5E%7B-2%7D+%2B5%2A10%5E%7B-4%7D+%3D3%2A+%5Cfrac%7B1%7D%7B10%7D+%2B1%2A+%5Cfrac%7B1%7D%7B10%5E%7B2%7D+%7D%2B5%2A+%5Cfrac%7B1%7D%7B10+%5E%7B4%7D+%7D+%3D+%5C%5C++%5Cfrac%7B3%7D%7B10%7D+%2B1%2A+%5Cfrac%7B1%7D%7B100%7D+%2B5%2A+%5Cfrac%7B1%7D%7B10000%7D%3D+%5Cfrac%7B3%7D%7B10%7D%2B+%5Cfrac%7B1%7D%7B100%7D%2B+%5Cfrac%7B1%7D%7B2000%7D+%3D+++%5Cfrac%7B600%7D%7B2000%7D+%2B+%5Cfrac%7B20%7D%7B2000%7D%2B++%5C%5C+++%5Cfrac%7B1%7D%7B2000%7D%3D+%5Cfrac%7B621%7D%7B2000%7D+%3D0.3105)
Существует такая формула a^-x=1/a^x -формула степеней, можешь поискать. Например 10^-5=1/10^5=1/100000 или 30^-2=1/30^2=1/900 или 2^-5=1/2^5=1/32
Домножим и разделим на cos(π/18)
(sinπ/18*cosπ/18*cosπ/9*cos2π/9)/cosπ/18=
=(sinπ/9*cosπ/9*cos2π/9)/(2cosπ/18)=
=(sin2π/9*cos2π/9)/(4cosπ/18)=
=(sin4π/9)/(8cosπ/18)=
=sin(π/2-π/18)/(8cosπ/18)=
=(cosπ/18)/(8cos(π/18)=
=1/8
9a²+6a+1-4b²=(3a+1)²-(2b)²=(3a+1-2b)(3a+1+2b)
25a²-(4b²-4b+1)=(5a)²-(2b-1)²=(5a-2b+1)(5a+2b-1)
(10n + 5)² = 100n(n + 1) + 25
Воспользуемся формулой квадрата суммы
100n² + 100n + 25 = 100n² + 100n + 25
(25 у вас лишняя в левой части)
а) 35² = (30 + 5)² = 900 + 300 + 25 = 1225
б) 55² = (50 + 5)² = 2500 + 500 + 25 = 3023
в) 85² = (80 + 5)² = 6400 + 800 + 25 = 7225
г) 125² = (100 + 25)² = 10000 + 5000 + 625 = 15625
(y-y₁)/(y₂-y₁)=(x-x₁)/(x₂-x₁);
(y+5)/9=(x+1)/3;
y+5=3x+3;
y=3x-2;
Ответ: k=3; b=-2;
уравнение прямой: y=3x-2;