Answer:
a) P=2(L+W)
b)
c)-2 inch/hour
Step-by-step explanation:
given:
length of the rectangle as L inches
width of the rectangle as W inches
a) The perimeter is defined as <u>the measure of the exterior boundaries</u>
therefore, for the rectangle the perimeter 'P' will be
P= length of AB+BC+CD+DA (A,B,C and D are marked on the figure attached)
Now from figure
P= L+W+L+W
OR
=> P=2L+2W .....................(1)
b)now dp/dt can be found as by differentiating the equation (1)
.............(2)
c)Now it is given for the part c of the question that
L=40 inches
W=104 inches
dL/dt=2 inches/hour
dW/dt= -3 inches/hour (here the negative sign depicts the decrease in the dimension)
substituting the above values in the equation (2) we get