4/9x=3.6
4/9x=3 6/10
4/9x=36/10
x=36/10:4/9=324/40=8 1/10=8.1
8×99×12562×498-62×398= 4954629116
y'=[ cosx * 3x- sinx*3 ] /9x^2 = [ 3xcosx-3sinx] /9x^2 = [ xcosx-sinx ] / 3x^2
y'= [ -2sin2x *3x - cos2x*3 ] / 9x^2 = [ -6xsin2x-3cos2x ] /9x^2=
=[ -2xsin2x-cos2x]/3x^3
Решение:
124 - 24 * (480 / х - 56) = 28
124 - 11520 / х + 1344 = 28
11520 / х = 1440
х = 11520 / 1440
х = 8