√3·cos²15°- √3·sin²15°=<span>√3</span>·<span>(cos</span>²<span> 15°- sin</span>²<span> 15°) =</span>√3·сos(2·15⁰)=√3·cos30⁰=√3·√3/2=3/2=1,5
5m³-mn+n²+m+2n+2mn-m²-n²-7m³+n-9m=-2m³+mn-5m²+3n-8m
5m³-mn+n²-4m²+m+2n-2mn+m²+n²+7m³-n+9m=12m³+2n²-3m²-3mn+10m+n
Ну наверно -4 целых и одна вторая
Жауап:
(2+х)^3 = 8+12х+ 6х^2 + х^3