A one-dimensional linear element is used to approximate the temperature variation in a fin. The solution gives the temperature at two nodes i and j of an element as 100 and 80°C respectively. The distance from the origin to node i is 6 cm and to node j is 10 cm. Determine the temperature at a point 9 cm from the origin. Also, calculate the temperature gradient in the element. Show that the sum of the shape functions at the location 9 cm from the origin is unity.