Verify that your answer to part (c)(ii) and the result from part (b)(i) both give the same value for the gradient of the tangent to the curve at the point .
An international mission has landed a rover on the planet Mars. After landing, the rover deploys a small drone on the surface of the planet, then rolls away to a distance of 6 metres in order to observe the drone as it lifts off into the air. Once the rover has finished moving away, the drone ascends vertically into the air at a constant speed of 2 metres per second.
Let be the distance, in metres, between the rover and the drone at time seconds.
Let be the height, in metres, of the drone above the ground at time seconds. The entire area where the rover and drone are situated may be assumed to be perfectly horizontal.
the rate at which the distance between the rover and the drone is increasing at the moment when the drone is 8 metres above the ground.
(ii)
the height of the drone above the ground at the moment when the distance between the rover and the drone is increasing at a rate of .
Question 9a
Marks: 3
In the diagram below, is the outline of a type of informational signboard that a county council plans to use in one of its parks. The shape is formed by a rectangle , to one side of which an equilateral triangle has been appended.
The signboards will be produced in various different sizes. However because of the cost of the edging that must go around the perimeter of the signboards, the council is eager to design the signboards so that the area of a signboard is the maximum possible for a given perimeter.
Let and let .
a)
(i)
Write down an expression in terms of and for the perimeter of the signboard, .