If x = sin⁻¹(sin10) and y = cos⁻¹(cos10), then y - x is equal to:

y = cos⁻¹(cos10) and x = sin⁻¹(sin10)
answer is not zero , it means here 10 is in radian not in degree. so, 10 = 10π/π = 10π(22/7) = 70π/22 = 35π/11 = (33π + 2π)/11 = 3π + 2π/11
we know, y = cos⁻¹(cosA) = A if 0 < A < π
see graph of cos⁻¹(cosx)
here it is clear that, graph between 3π to 4π
so, equation of line between 3π to 4π: Y - π = (0 - π)(4π - π)(X - π)
Y - π + (X - π) = 0
X + Y - π = 0
so, Y = 4π - X
so, y = cos⁻¹(cos10) = 4π - 0
again, for x = sin⁻¹(sin10)
see graph, between 3π to 7π/2 [ because 3π + 2π/11 lies between them ]
here, equation of line lies between 3π to 7π/2
points are (5π/2, π/2) and (7π/2, -π/2)
is Y + π/2 = (-π/2 - π/2)(7π/2 - 5π/2)(X - 5π/2)
Y + π/2 + (X - 5π/2) = 0
Y + X - π = 0
Y = 3π - X
hence, x = sin⁻¹(sin10) = 3π - 0
now, y - x = 4π - 0 - (3π - 0) = π
hence, answer should be π