If -LSB- math -RSB- x + y = 2 -LSB- / math -RSB- and -LSB- math -RSB- x ^ 2 + y ^ 2 = 2 -LSB- / math -RSB- , what is the value of -LSB- math -RSB- xy -LSB- / math -RSB- ?
What would be an intuitive way of seeing that this math expression : | x | ^ 2 + -LRB- y - | x | ^ -LRB- 2/3 -RRB- -RRB- ^ 2 = 1 plots as a heart ?