let xy=4 and let dy/dt=1 find dx/dt when x=2
1 Answer
justaguide | College Teacher | (Level 2) Distinguished Educator
The variables x and y are related by `xy=4` .
Take the derivative with respect to t.
=> `x*(dy/dt) + y*(dx/dt) = 0` ...(1)
When x = 2, y = 2. Also `dy/dt = 1` . Substituting these values in (1)
`2*1 + 2*(dy/dt) = 0`
=> `dy/dt = -1`
The required value of `dy/dt = -1` .