<h3>sin4x + sin2x = 0</h3>
sin2x = 2•sinx•cosx - синус двойного аргумента
<h3>2•sin2x•cos2x + sin2x = 0</h3><h3>sin2x•(2cos2x + 1) = 0</h3><h3>1) sin2x = 0 ⇔ 2x = πn ⇔ x = πn/2, n ∈ Z</h3><h3>2) 2cos2x + 1 = 0 ⇔ cos2x = - 1/2 ⇔ 2x = (± 2π/3) + 2πk ⇔ x = (± π/3) + πk, k ∈ Z</h3><h3><em><u>ОТВЕТ: πn/2, n ∈ Z ; (± π/3) + πk, k ∈ Z</u></em></h3><h3><em><u /></em></h3>
√150*√108/√180 =√150*108/180 =√5*108/6=√5*18=√5*2*9=3√10
1)<span>-4+7х=9 : 7х=9+4: 7х=13: х= 7/13 (это дробь) </span>
Х+у=7; х=7-у; у=7-х
х-у=10; х=10+у; х-10.