12. Area The included angle of the two sides of constant equal length 5' of an isosceles triangle is 6. (a) Show that the area of the triangle is given by A = is 2 sin 6. (b) The angle 6 is increasing at the rate of; radian per minute. Find the rates of change of the area when 6 = 77/ 6 and 6: 7/3. (c) Explain why the rate of change of the area of the triangle is not constant even though d6/dt is constant