1) 1. 7*10^-5/36 * 6^4/0,0042 =
= (7*10^-5 / 36) * (6^4 * 10000 / 42) = (10^-5 / 9) * (6^4 * 2500 / 6) = (1 / 9*10^5) * 6^3 * 2500 = (1 / 9*100000) * 216 * 2500 = (1/40) * 24 = (1/5) * 3 = 3/5.
2. 7,7/0,45 * 2,7/28=
= (77*100 / 10*45) * (27 / 10*28) = (11*10 / 5) * (3 / 10*4) = 11/5 * 3/4 = 33/20.
3. В условии знак какой-то пропущен
2) ответ - 4)
<span>54,4-37,82:(4,96+7,44)= 51,35
1) 4,96+7,44=12,4
2) 37,82:12,4=3,05
3) 54,4-3,05=51,35</span>
![2sin^2a-3cos^2(-a)=2sin^2a-3cos^2 a=2*(1-cos^2 a)-3cos^2 a=2-2cos^2 a-3cos^2 a=2-5cos^2 a](https://tex.z-dn.net/?f=2sin%5E2a-3cos%5E2%28-a%29%3D2sin%5E2a-3cos%5E2%20a%3D2%2A%281-cos%5E2%20a%29-3cos%5E2%20a%3D2-2cos%5E2%20a-3cos%5E2%20a%3D2-5cos%5E2%20a)
![-1 \leq cos a \leq 1;\\\\0 \leq cos^2 a \leq 1;\\\\-1 \leq -cos^2 a \leq 0;\\\\5*(-1) \leq 5*(-cos^2 a) \leq 5*0;\\\\-5 \leq -5cos^2 a \leq 0;\\\\2+(-5) \leq 2+(-5cos^2 a) \leq 2+0;\\\\-3 \leq 2-5cos^2 \leq 2;](https://tex.z-dn.net/?f=-1%20%5Cleq%20cos%20a%20%5Cleq%201%3B%5C%5C%5C%5C0%20%5Cleq%20cos%5E2%20a%20%5Cleq%201%3B%5C%5C%5C%5C-1%20%5Cleq%20-cos%5E2%20a%20%5Cleq%200%3B%5C%5C%5C%5C5%2A%28-1%29%20%5Cleq%205%2A%28-cos%5E2%20a%29%20%5Cleq%205%2A0%3B%5C%5C%5C%5C-5%20%5Cleq%20-5cos%5E2%20a%20%5Cleq%200%3B%5C%5C%5C%5C2%2B%28-5%29%20%5Cleq%202%2B%28-5cos%5E2%20a%29%20%5Cleq%202%2B0%3B%5C%5C%5C%5C-3%20%5Cleq%202-5cos%5E2%20%5Cleq%202%3B)
наименьшее значение -3, наибольшее 2
Tg(a-b)=(tga-tgb)/(1+tga*tgb)=(2-1)/(1+2)=1/3
a1 = - 5
a2 = 2,3
d = a2 - a1 = 7,3
a4 = a1 + 3d = - 5 +3*7,3 = 16,9
S4 - ?
S4 = (a1 + a4)/2*4 = 2*( - 5 + 16,9) = 23,8