4tg4x*1/2*sinx*cosx-tg4x=0
2tg4x*1/2sin2x-tg4x=0
tg4x*sin2x-tg4x=0
tg4x*(sin2x-1)=0
tg4x=0⇒4x=πn⇒x=πn/4,n∈z
0≤πn/4≤π
0≤n≤4
n=0⇒x=0
n=1⇒x=π/4
n=2⇒x=π/2
n=3⇒x=3π/4
n=4⇒x=π
sin2x-1=0
sin2x=1⇒2x=π/2+2πk⇒x=π/4+πk
0≤π/4+πk≤π
0≤1+4k≤4
-1≤4k≤3
-1/4≤k≤3/4
k=0⇒x=π/4
А)1/3+1/5+1/2=10/30+6/30+15/30=
31/30=1 1/30
б)3/5+1/6+1/2=18/30+5/30+15/30=
38/30=1 4/15