Х²=1/2
х₁,₂=√1/2
х₁=√1/2
х₂=-√1/2
<span>Найти множество значений функции y = cos</span>²<span> (x) - sin(x)</span>
Решение
<span>|cosx| ≤ 1</span>
<span> -1 ≤ cosx ≤ 1,
0 ≤ cos</span>²<span>(x) ≤ 1
</span><span>|sin x| ≤ 1
</span><span>-1 ≤ sinx ≤ 1,
</span><span>-1 ≤ -sinx ≤ 1,
</span><span>0 -1 ≤ <span>Cos</span></span>²<span><span>x – sinx </span>≤ 1+ 1
</span><span>-1 ≤ <span>Cos2x – sinx </span>≤ 2</span>
<span>Ответ: [- 1 ; 2].</span>
(х+3)(х-4)=-6
х²-х-12+6=0
х²-х-6=0
D=1+24=25
х1=3
х2=-2
х(х-5)+99+15(х-5)=0
х²-5х+99+15х-75=0
х²+10х+24=0
D=4
х1=-6
х2=-4
3х(х+5)+88-20(х+5)=0
3х²+15х+88-20х-100=0
3х²-5х-12=0
D=169
х1=3
х2=-8/6=-4/3