The equation is .

(a).

Graph :

Graph for the equation .

(b).

Fins the tangent curves at .

Substitute  in the equation .

and

and

  and

The points are , ,,

 The function is .

Apply derivative on each side with respect to .

The slope at the point

The tangent line is

The slope at the point

The tangent line is

.

The slope at the point .

The tangent line is

.

The slope at the point .

The tangent line is

.

(b).

Graph :

Graph for the four tangents.

(a).

(b).The tangent points are , ,,

(c).