ДОКАЖИТЕ ТОЖДЕСТВО ПЛИЗЗЗЗЗЗЗ sin(2a+b)/sina - 2cos(a+b)=sinb/sina

sin(2a+b)/sina - 2cos(a+b)=sinb/sina (sin2a*cosb+cos2a*sinb)/sina - 2(cosa*cosb - sina*sinb) = = (2*sina*cosa*cosb+sinb(cos^2 a - sin^2 a))/sina - 2(cosa*cosb-sina*sinb)= = 2cosa*cosb + sinb*cos^2 a/sina - sinb*sin^2 a/sina - 2cosa*cosb + +2sina*sinb = = sinb*cos^2 a/sina + sina*sinb = = sinb(cos^2 a + sin^2 a)/sina = = sinb / sina sinb / sina = sinb / sina Доказано!

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