61
Chapter 7: Implicit Differentiation
420. x
2
+ 2xy + y
2
= 1 at (0, 1)
421. cos(xy) + x
2
= sin y at 1 2
, π
( )
422. y
2
( y
2
– 1) = x
2
tan y at (0, 1)
Finding Equations of Tangent
Lines Using Implicit
Differentiation
418–422 Find the equation of the tangent line at the
indicated point.
418. x
2
+ xy + y
2
= 3 at (1, 1)
419. 3
2 5
2
2
2
2
2
x
y
x
y
+
(
) =
−
(
) at (2, 1)
Chapter 7: Implicit Differentiation
420. x
2
+ 2xy + y
2
= 1 at (0, 1)
421. cos(xy) + x
2
= sin y at 1 2
, π
( )
422. y
2
( y
2
– 1) = x
2
tan y at (0, 1)
Finding Equations of Tangent
Lines Using Implicit
Differentiation
418–422 Find the equation of the tangent line at the
indicated point.
418. x
2
+ xy + y
2
= 3 at (1, 1)
419. 3
2 5
2
2
2
2
2
x
y
x
y
+
(
) =
−
(
) at (2, 1)