13.
a) При у= -1
cosx= -1
x=π+2πk, k∈Z
При к=2 x=π+2π*2=5π
б) При у=1/2
cosx=1/2
x₁=π/3 + 2πk, k∈Z
При к=2 x=π/3 + 2π*2 = π/3 + 4π = 13π/3
x₂= -π/3 + 2πk, k∈Z
При к=2 x= -π/3 + 2π*2= -π/3 + 4π = 11π/3
Ответ: 11π/3; 13π/3; 5π.
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12*(-3/4)-3*5/6=-9-2,5=-11,5
(√11-1)² = 10 ...........
А)
=а^2-49
б)
=н^2-16м^2
в)
=0.04х^2-36у^6
г)
=9/49х^12-0.49у^6