1) cos^2 a = 1- sin^2 a
<span>cos^2 a = 1 - (1/3)^2
</span>cos^2 a = 1 - 1/9
cos^2 a = +- корень (8/9)
соs a = +корень8 / 3
2) <span>log два 32 +logтри27 - 7 = 5 + 3 -7=1
3)</span><span>logдва 16+logпять25-logтри81 = 4 + 2 - 4=2</span>
А)-5,2-(-3,8)= -5,2 +3,8 = -1,4. б)-7 6/7 : (-9 3/7 )= - 55/7 : (- 66/7) = - 55/7 * (- 7/66) = 5/6. в) -0,75* 3.2 = - 2,4. г)6/7* (-2 13/18)= -2 1/3 2. -1,73 * 5/9 -5/9 * 2,77 = 5/9* (-1,73-2,77)= 5/9*(-4,5)= -2,5
3. 6(3-0,5с) -2(0,8с-3)= 18-3с-1,6с+6= -4,6с+24
4. 2/3(х-3)-3/5(х-10)=5
2/3х-2-3/5х+6=5
2/3х-3/5х= 5-6+2
10/15х- 9/15х = 1
1/15х = 1
Х = 15
Ответ:15
5. |-1 11/14|=|-6,25|*|х|
1 11/14=6,25х
х=1 11/14: 6,25= 1 11/14* 100/625= 2/7
3+1i=√10*e^(i*arctg(1/3)); 1*i-2=√5*e^(-arctg (0,5))⇒3+i/i-2=√10*e^(i*arctg(1/3))/√5*e^(-i*arctg (0,5))=√2*e^(arctg(1/3)+arctg(0,5)).
0,0000009
0,0000008
0,0000007