4sin810+3cos720-3sin630+5cos900=4sin(720+90)+3cos(2*360)-3sin(720-90)+5cos(720+180)=4sin90+3cos0+3sin90+5cos180=4*1+3*1+3*1+5*(-1)10-5=5=5
<span>(1+3<span>x)+(x^2-2x)-(2x^2-x)=</span> 1+3<span>x+x^2-2x-2x^2</span>+x=- <span>x^2</span>+2<span>x+1</span></span>
Cos(2П-2x)+3sin(П-x)=2
cos2x + 3sinx = 2
1 - 2sin²x + 3sinx - 2 = 0
2sin²x - 3sinx + 1 = 0
sinx = t
2t² - 3t + 1 = 0
D = 9 - 4*2*1 = 1
t₁ = (3 - 1)/4
t₁ = 1/2
t₂ = (3 + 1)/4
t₂ = 1
1) sinx = 1/2
x = (-1)^n *arcsin(1/2) + πk, k∈Z
x₁ = (-1)^n* (π/6) + πk, k∈Z
2) sinx = 1
x₂ = π/2 + πn, n∈Z
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