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HOT PRACTICE TEST

Chapter 6 – Application of Derivatives

Class XII Mathematics • 25 Marks • 60 Minutes

Increasing and Decreasing Function

Turning point

Section A – 6 × 1 = 6

1. What does f′(x)>0 indicate about f(x)?
2. What does f′(x)<0 indicate?
3. State the first derivative condition for a local maximum.
4. State the first derivative condition for a local minimum.
5. Find the critical point of f(x)=x²−4x+3.
6. What is the geometrical meaning of f′(x)?

Section B – 3 × 2 = 6

1. Find the intervals in which f(x)=x²−6x+5 is increasing or decreasing.
2. Find the critical points of f(x)=x³−3x².
3. Determine whether x=0 is a maximum or minimum for f(x)=x².

Section C – 3 × 3 = 9

1. Find the maximum and minimum values of x+1/x for x>0.
2. Find the equation of the tangent to y=x² at x=2 and interpret its slope.
3. Find the dimensions of a rectangle of maximum area having perimeter 40 units.

Section D – 1 × 4 = 4

1. A rectangular sheet has perimeter 60 cm. Using derivatives, determine its dimensions for maximum area and prove that the result gives a maximum.