1) соs 2a = 1 - 2sin^2 a = 1- 2(-8/17)^2 = 161/289
=25^(5/4+(-5/12)-1/3)=25^(15/12 - 5/12 - 4/12) = 25^(6/12) = 25^(1/2) = √25 = 5
10*корень 0,25+1/26*корень169=10*0,5+1/26*13=5 + 13/26
1. (13/18)*(9/26)=0.25
2. 4.625-0.25=4.375
3. 2 1/4=9/4
4. 9/4=2.25
5. 4.375:2.25=(35/18)
6. 2 1/2=5/2
7. 5/2=2.5
8. 2.5:1.25=2
9. 6 3/4=27/4
10. 27/4=6.75
11. 2:6.75=(8/27)
12. (35/18)+(8/27)=(121/5413. 1 53/68=121/68)
13. 1 53/68=121/68
14. (121/54):(121/68)=(34/27)
<span>25x^2 = 1
х^2=1/25
x=1/5
x= -1/5
</span>