6 7/12 - 3 17/36 = 3 1/9
3 1/9 • 2,5= 70/9
4 1/3:0,65=20/3
70/9-20/3=10/9= 1 1/9
<span>181 - 8 *r = 45
8r=181-45
8r=136
r=136/8
r=17
</span>
1 - cos П/4 + cos^2 П/4 - cos^3 П/4...=(1+сos^2П/4+сos^4П/4+...)-
(cosП/4+сos^3П/4+...)=(1-сosП/4)/(1-сos^2П/4)=1/(1+sqrt(2)/2)=2-sqrt(2)