The function is

To find the slope of tangent line, derivative with respect to x to the above function.

Substitute in the above equation.

To find the y-coordinate of the point, substitute in the original function.

The point-slope from of line equation is , where m = slope and is point.

Substitute  in the point-slope form of line equation.

The tangent line equation is .

(b).

The function is

Apply first derivative with respect to x.

Apply second derivative with respect to x.

Because when and is defined on the real line, we should be test for concavity in the interval .

Interval                Test Value                   Sign of                          Conclusion

                   Concave upward