A solution (x, y) of x2+2xsinxy+1=0 is
(1, 0)
(1, 7π/2)
(– 1, –7π/2)
(– 1, 0)
When x=1, 2+2sin y=0⇒sin y=−1and 7π2=sin 3π+π2=−1
So (1, 7π/2) is a solution.
For x = – 1, sin y = 1 which is not satisfied by y = 7π/2 or 0.