у=lnx/cosx
y'=((lnx')*cosx -lnx *(cosx)')/cos^2x=(cosx/x +lnxsinx)/cos^2x
<span>А)
29²= (30-1)</span>² <span>= 30</span>² - 2·30·1 +<span>1</span>² = 900 - 60 + 1 = 841<span>
Б)
79²=(80-1)</span>² <span>= 80</span>² - 2·80·1+1² = 6400 - 160 +1 = 6241<span>
В)
9,8²=</span>(10-0,2)² = 10² - 2·10·0,2 + 0,2² =100 - 4 + 0,04 = 96,04<span>
Г)
4,7²= (5-0,3)</span>² = 5² - 2·5·0,3 + 0,3² = 25 -3+0,09 = 22,09
Cos x= п/3, т.к. п/3€[0;п]
х= 1/2