Recent questions and answers in CBSE XII

Prove that every real valued function which is derivable at a point of its domain is also continuous at that point. Is the converse true?

answered May 18, 2023 by sbi071403

1 answer

Show that the function $ f : Z \rightarrow Z $ defined by $ f(x)=x^2$ is neither one-one nor onto.

answered Sep 9, 2022 by hackerboyqwerty123

1 answer

A calculator manufacturing company finds that the daily cost of producing calculators is given by C(x) = 200x + 7500. • If each calculator is sold for Rs. 350, find the minimum number of calculators that must be produced daily and sold to ensure no loss. • If the selling price is increased by Rs. 150, what would be the break-even point?

answered Jun 20, 2022 by thor69565

1 answer

Assertion: Artificial seeds can be produced using tissue culture. <br> Reason: Artificial seeds can be strored and propagated just as natural seeds.

answered Jul 30, 2021 by ramniranjan1962

1 answer

Let * be a binary operation on the set of real numbers. If a * b = a+b-ab, 2 * ( 3 * x ) = -7, find the value of x.

answered Apr 26, 2021 by kuppurajanbharathi

1 answer

A, B and C are engaged in a printing business. A being the working partner, receives 10% of the net profit as salary. The remaining profit is divided among themselves in the ratio 4:5:9. If A gets in total Rs. 3,00,000, find the total profit in the business and the shares of B and C in it.

answered Dec 22, 2020 by makumarsahu2004

1 answer

A furniture firm manufactures chairs and tables, each requiring the use of three machines A, B and C. Production of each chair requires 2 hours on machine A, 1 hour on machine B and 1 hour on machine C. Each table requires 1 hour each on machine A and B and 3 hours on machine C. The profit obtained by selling one chair is Rs. 30 while by selling one table the profit is Rs. 60. The total time available per week on machine A is 70 hours, on machine B is 40 hours and on machine C is 90 hours. How many chairs and tables should be made per week so as to maximise profit? Formulate the problem as LPP and solve it graphically.

answered Dec 11, 2020 by ms21012003

1 answer

What is the Role of Catalyst in a Chemical Reaction

answered Nov 4, 2020 by shresthasushma628

2 answers

Find the present worth of an ordinary annuity of Rs. 1,200 per annum for 10 years at 12% per annum, compounded annually. [Use (1.12) -10 =0.3221]

answered Oct 31, 2020 by sarikabora999

1 answer

There are two families P and Q. There are 3 men, 3 women and 12 children in family P and 2 men, 2 women and 4 children in family Q. The recommended daily allowance for calories is : Man : 2400, woman : 2000, child: 1400 and man : 60 g for proteins is : woman: 40 g and child: 35 g. (i) Represent the above information by matrices. Using matrix multiplication, calculate the total requirement of calories and proteins of each of the two families.

answered Oct 25, 2020 by sharmaaseem2406

1 answer

Solve the following LPP graphically. Maximize or minimize Z = 3x+5y subject to \[3x-4y\geq-12\]\[2x-y+2\geq0\]\[2x+3y-12\geq0\]\[0\leq x\leq4\]\[y\geq2\]

answered Oct 19, 2020 by rvandana115

1 answer

A pure inductor is connected across an a.c. source. Show mathematically that the current in it lags behind the applied e.m.f by a phase angle of $\large\frac{\pi}{2}$ What is its inductive reactance? Draw a graph showing variation of inductive reactance with the frequency of the a.c. source.

answered Oct 17, 2020 by badalbhardwaj2

1 answer

Most common monomer of carbohydrate is

answered Oct 6, 2020 by taneeshdx999

1 answer

A toy company manufactures two types of dolls, A and B. Each doll of type B takes twice as long as to produce as one of type A. If the company produces only type A. It can make a maximum of 2000 dolls per day. The supply of plastic is sufficient to produce 1500 dolls per day. Type B requires a fancy dress which cannot be available for more than 600 per day. If the company makes profit of Rs.3 and Rs.5 per doll respectively on doll A and doll B, how many of each should be produced per day in order to maximise the profit?

answered Oct 5, 2020 by rise.sparkle13

1 answer

Solve:\[ydx-(x+2y)^2dy=0\]

answered Oct 1, 2020 by gilledobaleros

1 answer

Important site of formation of glycoproteins and glycolipids is

answered Sep 13, 2020 by pady_1

1 answer

The term “CPR” often used in first aid stands for

answered Aug 31, 2020 by murugesan9486089328

1 answer

In human females, menstruation can be defined by administration of

answered Jul 19, 2020 by kphasnashirin

1 answer

The inheritance of flower colour in Antirrhinum is an example of

answered Jul 19, 2020 by kphasnashirin

1 answer

Using matrices, solve the following : $2x+y-3z=13; x+y-z=6 ;2x-y+4z = -12$

answered Jul 9, 2020 by hjaspinder

1 answer

Several plant and animal species present together at a place constitute a

answered Jul 8, 2020 by andyrich1972november

1 answer

If at high altitudes , birds become rare, plants likely to disappear are:

answered Jun 19, 2020 by abhicjraj

1 answer

First code of every mRNA is

answered May 28, 2020 by sarthakj451

1 answer

Use definite integration, find the area of triangle whose vertices are (-1,6),(1,2) and (5,4).

answered May 21, 2020 by sreejaunnikrishnan161

1 answer

The given graph shows the range of variation among population members for a trait determined by mutated genes. If this population is subjected to disruptive selection for several generations, which of the following distribution is most likely to result?

answered May 8, 2020 by kimbbrownn

1 answer

In the given food web, an increase in the population of hawks will not result in

answered Apr 11, 2020 by srivastavshivam359

1 answer

Which one is useful to remove oil stains in laundry?

answered Apr 4, 2020 by faisalsergio16

1 answer

An AC voltage of peak $20\;V$ is connected in series with a silicon diode and a load resistance of $500 \Omega$. The forward resistance of the diode is $10 \Omega$ and the barrier voltage is $0.7\;V$. Find the peak current through diode and the peak voltage across the load. What will happen to these values if the diode is assumed to be ideal?

answered Apr 2, 2020 by manishkr1456

1 answer

Show that the area enclosed by the circle $ x^2+y^2=64a^2$ and the parabola $y^2=12ax$ is $ a^2 \bigg(\frac{16}{\sqrt 3}+\large\frac {64\pi}{\sqrt 3}\bigg)$

answered Apr 1, 2020 by aparme03

1 answer

Which one of the following feature is common to prokaryotes and many eukaryotes?

answered Mar 21, 2020 by bhushu559

1 answer

Let $f:R_+\rightarrow[-5,\infty) $ given by $f(x)=9x^2+6x-5.$ show that f is invertiable with $ f^{-1}(y)=\frac{\sqrt{y+6}-1}{3}.$

answered Mar 21, 2020 by hk0312109

1 answer

Which of the following statement is/are not correct for single cell proteins?i. The biomass is obtained from unicellular microorganisms only. ii. It provides protein rich supplements iii. SCP can be produced by bacteria and algae but not fungi. iv. It helps to minimize environmental pollution. v. SCP has be processed before use

answered Mar 20, 2020 by hr4096204

1 answer

Give an example to show that the relation R in the set of natural numbers, defined by $ R = ( (x,y), x, y \in\: N, x \leq \: y^2) $ is not transitive.

answered Mar 20, 2020 by neelurani06041980

1 answer

The area of the region in the first quadrant enclosed by the x-axis,the line y=x and the circle $x^2+y^2=32$ is \begin{array}{1 1}(A)\;16\pi\; sq.units & (B)\;4\pi \;sq.units\\(C)\;32\pi\; sq.units & (D)\;24\pi\;sq.units \end{array}

answered Mar 17, 2020 by kharbans823

2 answers

Which one is related with steroids?

answered Mar 17, 2020 by shivayfitness45

2 answers

What is the degree of the following differential equation? $ y\large\frac{d^2y}{dx^2}+\bigg(\frac{dy}{dx} \bigg)^3$$=x \bigg( \large\frac{d^3y}{dx^3} \bigg)^2 $

answered Mar 17, 2020 by anilmathappsc

1 answer

Find the order and degree of the differential equation $\bigg[ 1+ \bigg(\large \frac{dy}{dx} \bigg)^2 \bigg]^{\large\frac{3}{2}} = \frac{d^2y}{dx^2} $

answered Mar 17, 2020 by anilmathappsc

1 answer

Find the area of the region enclosed between the circles $ x^2+y^2=1\;and\;\bigg(x-\frac{1}{2}\bigg)^2+y^2=1$

answered Mar 16, 2020 by msq6786

1 answer

How does primary sludge differ from activated sludge? What type of changes in the sludge is carried out in anaerobic sludge digester? Give the composition of biogas produced in the sewage treatment plant.

answered Mar 12, 2020 by momisingh14

2 answers

Let X denote the sum of the numbers obtained when two fair dice are rolled. Find the variance and standard deviation of X.

answered Feb 18, 2020 by surafelalemgirma91

2 answers

Find the equation of the plane passing through the intersection of planes $ 4x-y+z=10\: and \: x+y-z=4$ and parallel to the line with direction ratios < 2, 1, 1>. Find also the perpendicular distance of (1, 1, 1) from the plane.

answered Feb 17, 2020 by jyotiverma221997

1 answer

Given figure represents the maturation of pro insulin into insulin. Identify the product A.

answered Jan 22, 2020 by vishup1912

1 answer

Fruit shape in Shepherd’s purse (Capsella bursa) is of two types- triangular and top shaped. Triangular fruit shape (T) is dominant over top shape (t). Following table summarizes the results of the several crosses. Which pair of strains possess genotype Tt?

answered Jan 11, 2020 by badboyayandeep96

1 answer

A certain patient is suspected to be suffering from AIDS. Which diagnostic technique will you recommend for its detection?

answered Dec 29, 2019 by guptahema1975

1 answer

Which of the following is not required in the preparation of a recombinant DNA molecule?

answered Dec 29, 2019 by jaswalvipin1988

1 answer

Hormone responsible for the growth of root in micro propagation is

answered Dec 28, 2019 by diptichauhan3112

1 answer

Find the area of the segment cut off from the parabola $ y^2=2x$ by the line $ y=4x-1$

answered Dec 22, 2019 by gourishanker2431

1 answer

Choose the correct statement amongst the following

answered Dec 12, 2019 by mishraashish896

1 answer

Assertion: Asexual reproduction involves formation of clone of an organism <br> Reason: Clones are morphologically and genetically similar individuals.

answered Dec 10, 2019 by madhurihodscience

1 answer

Find the volume of the tetrahedron formed by the four planes $x+y=0,y+z=0,z+x=0,x+y=1$

asked Jul 9, 2019 by meena.clay6

1 answer

Ask Questions, Get Answers