x^2 = 4/25
x1= 0,4 и x2= - 0,4
Сos (3x +π/6)+ Сos (x + π<span>/4 ) = 0
есть формула: Cos</span>α + Cosβ = 2Sin(α+β)/2 * Sin(α-β)/2
применим её:
2Sin(3x +π/6 +x +π/4)/2 * Sin((3x +π/6 -x -π/4)/2= 0
2Sin(2x +5π/24) *Sin(x -π/24) = 0
Sin(2x +5π/24) = 0 или Sin(x -π/24)= 0
2х + 5π/24 = πn, n ∈Z x - π/24 = πm, m ∈Z
2x = πn - 5π/24, n ∈ Z x = πm + π/24 , m ∈Z
x = πn/2 -5π/48, n ∈Z
㏒₂216*㏒₅25- 3㏒₂4 =㏒₂ 216*㏒₅5² +3㏒₂2²=㏒₂216*2㏒₅5 -3*2㏒₂2=
= ㏒₂216* 2 - 6
㏒₂256*㏒₅25- 3㏒₂4 =㏒₂ 2⁸ *㏒₅5² +3㏒₂2²= 8㏒₂2* 2㏒₅5 - 3*2㏒₂2=
= 8 * 2 - 6 =10
(х+5)(х+6)+9=0
х+5=0 или х+6=0 или х+9=0
х=0-5. х=0-6. х=0-9
х=-5. х=-6. х=-9