Sin(π/2 + x) - Cos(π - x) + 1 = 0
Sin(a+b) = Sina*Cosb + Cosa*Sinb
Cos(a-b) = Cosa*Cosb + Sina*Sinb
1)Sin(π/2 + x) = Sin(π/2)*Cosx + Cos(π/2)*Sinx = Cosx
Cos(π - x) = Cosπ*Cosx + Sinπ*Sinx = -Cosx
Cosx - (-Cosx) + 1 = 0
2Cosx + 1 = 0
Cosx = -1/2
x = ±2π/3 + 2πn, n∈Z
Sina - Sinb = 2Sin((a-b)/2)*Cos((a+b)/2)
2) Sin(7x) = Sin(5x)
Sin(7x) - Sin(5x) = 0
2Sinx *Cos(6x) = 0
Sinx = 0 => x = πn, n∈Z
Cos(6x) = 0 => 6x = π/2 + 2πn, n∈Z
x = π/12 + πn/3, n∈Z
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Sin(π/2 + x) - Cos(π - x) + 1 = 0
Sin(a+b) = Sina*Cosb + Cosa*Sinb
Cos(a-b) = Cosa*Cosb + Sina*Sinb
1)Sin(π/2 + x) = Sin(π/2)*Cosx + Cos(π/2)*Sinx = Cosx
Cos(π - x) = Cosπ*Cosx + Sinπ*Sinx = -Cosx
Cosx - (-Cosx) + 1 = 0
2Cosx + 1 = 0
Cosx = -1/2
x = ±2π/3 + 2πn, n∈Z
Sina - Sinb = 2Sin((a-b)/2)*Cos((a+b)/2)
2) Sin(7x) = Sin(5x)
Sin(7x) - Sin(5x) = 0
2Sinx *Cos(6x) = 0
Sinx = 0 => x = πn, n∈Z
Cos(6x) = 0 => 6x = π/2 + 2πn, n∈Z
x = π/12 + πn/3, n∈Z