1)√28=√4*7=2<span>√7
2)</span>√99=√9*11=3<span>√11
3)</span>√160=√16*10=4<span>√10
4)</span>√147=√49*3=7<span>√3
5)0,2</span>√50=0,2*√25*2=0,2*5√2=1√2=<span>√2
6)-0.5</span>√8=-0.5*2√2=-1√2=-<span>√2
7)0.6</span>√175=0,6√25*7=0.6*5√7=3<span>√7</span>
<span>cos(π/5)*cos(2π/5)</span><span><span>=<span><span>sin(π/5)*cos(π/5)*cos(2π/5)/</span><span>sin(π/5)</span></span></span><span>=<span><span>sin(2π/5)*cos(2π/5)/</span><span>2sin(π/5)</span></span></span><span>=<span><span>sin(4π/5)/</span><span>4sin(π/5)</span></span></span><span>=<span>1/4</span></span></span>
пусть в первый день турист прошел Х киллометров, тогда во второй день он пройдёт Х-8 киллометров, а на третий Х-11 киллометров.
Х + Х - 8 + Х - 11= 50
3Х =31
Х = 10 целых 1/3
C^2+2c-a^2+2a=(c^2-a^2)+2(c+a)=(c-a)(c+a)+2(c+a)=(c+a)(c-a+2)