Derivative as Rate of Change

IMPORTANT

Derivative as Rate of Change: Overview

This topic covers concepts, such as, Application of Derivative, Rate of Change of Quantities, Derivative as (Instantaneous) Rate of Change of a Function & Instantaneous Rate of Change of a Function w.r.t. another Function etc.

Important Questions on Derivative as Rate of Change

HARD
IMPORTANT

The length x of a rectangle is decreasing at the rate of   5cm/minute  and the width y is increasing at the rate of   4cm/minute  When   x=8cmandy=6cm,  the rate of change of (a) the perimeter, b the area of the rectangle would be:

MEDIUM
IMPORTANT

A ladder 5m long is leaning against a wall. The bottom of the ladder is pulled along the ground, away from the wall, at the rate of   2cm s -2 . How fast is its height on the wall decreasing when the foot of the ladder is 4m away from the wall?

HARD
IMPORTANT

Water is running into an underground right circular conical reservoir, which is 10 m deep and radius of its base is 5 m. If the rate of change in the volume of water in the reservoir is 32πm3min, then the rate (in mmin) at which water rises in it, when the water level is 4 m, is

MEDIUM
IMPORTANT

If the volume of a sphere is increasing at a constant rate, then the rate at which its radius is increasing,is

MEDIUM
IMPORTANT

In which of the following range x lies such that 9x2-12x-40 increases more rapidly than 2x3+7.

EASY
IMPORTANT

At which point on the parabola x2=4y, the rate of increase of the x- coordinate is the same as the rate of the increase of y- coordinate

MEDIUM
IMPORTANT

If there is 2% error in measuring the radius of Sphere, then .......... will be the percentage error in the surface area.

EASY
IMPORTANT

If y=7x-x3 and x increases at the rate of 4 units per second, then the rate of change in slope of the curve when x=3, is

MEDIUM
IMPORTANT

A point on the parabola y2=18x at which the ordinate increases at twice the rate of the abscissa is:

EASY
IMPORTANT

At which point on the parabola x2=4y, the rate of increase of the x- coordinate is the same as the rate of the increase of y- coordinate.

EASY
IMPORTANT

A point on the parabola y2=18x at which the ordinate increases at twice the rate of the abscissa, is

EASY
IMPORTANT

The distance in meters covered by a body in t seconds, is given by s=3t2-8t+5.

The body will stop after

HARD
IMPORTANT

A company's profits, in thousands of dollars, can be modelled by the function: P(x)=0.08x3-1.9x2+12.5x, where x is the number of units sold (in millions) each week. Write down the values of x for which the instantaneous rate of change is zero. Justify your answer.

HARD
IMPORTANT

A company's profits, in thousands of dollars, can be modelled by the function: P(x)=0.08x3-1.9x2+12.5x, where x is the number of units sold (in millions) each week. State the values of x for which the instantaneous rate of change is positive. State the values of x for which the instantaneous rate of change is negative. Explain the meaning of each of these results.

HARD
IMPORTANT

A company's profits, in thousands of dollars, can be modelled by the function: P(x)=0.08x3-1.9x2+12.5x, where x is the number of units sold (in millions) each week. Calculate the instantaneous rate of change at x=3,x=8 and x=13. Explain the meaning of these values.

MEDIUM
IMPORTANT

The distance of a bungee jumper below his starting point can be modelled by the function f(t)=80t2-160t,0t2, where t is the time in seconds. Find f'(0.5) and f'(1.5) and comment on the values obtained.

MEDIUM
IMPORTANT

The distance of a bungee jumper below his starting point can be modelled by the function f(t)=80t2-160t,0t2, where t is the time in seconds. State the quantity represented by f'(t).

EASY
IMPORTANT

The distance of a bungee jumper below his starting point can be modelled by the function f(t)=80t2-160t,0t2, where t is the time in seconds.Find f'(t).

MEDIUM
IMPORTANT

The profit,  US$P ,made from selling cupcakes, c, is modelled by the function P=-0.056c2+5.6c-20. Find the rate of change of the profit. with respect to the number of cupcakes when c=20 and c=60 and comment your answers.

EASY
IMPORTANT

The profit,  US$P ,made from selling cupcakes, c, is modelled by the function P=-0.056c2+5.6c-20. Find dPdc.