Commerce (English Medium) Class 12 - CBSE Question Bank Solutions for Mathematics

If the sum of the surface areas of cube and a sphere is constant, what is the ratio of an edge of the cube to the diameter of the sphere, when the sum of their volumes is minimum?

AB is a diameter of a circle and C is any point on the circle. Show that the area of ∆ABC is maximum, when it is isosceles.

A metal box with a square base and vertical sides is to contain 1024 cm³. The material for the top and bottom costs Rs 5/cm² and the material for the sides costs Rs 2.50/cm². Find the least cost of the box.

The sum of the surface areas of a rectangular parallelopiped with sides x, 2x and `x/3` and a sphere is given to be constant. Prove that the sum of their volumes is minimum, if x is equal to three times the radius of the sphere. Also find the minimum value of the sum of their volumes.

If x is real, the minimum value of x² – 8x + 17 is ______.

The smallest value of the polynomial x³ – 18x² + 96x in [0, 9] is ______.

The function f(x) = 2x³ – 3x² – 12x + 4, has ______.

The maximum value of sin x . cos x is ______.

Maximum slope of the curve y = –x³ + 3x² + 9x – 27 is ______.

The maximum value of `(1/x)^x` is ______.

The curves y = 4x² + 2x – 8 and y = x³ – x + 13 touch each other at the point ______.

Evaluate the following:

`int x/(sqrt(x) + 1) "d"x`  (Hint: Put  `sqrt(x)` = z)

Evaluate the following:

`int sqrt(("a" + x)/("a" - x)) "d"x`

Evaluate the following:

`int x^(1/2)/(1 + x^(3/4)) "d"x`   (Hint: Put `sqrt(x)` = z⁴)

If A = `[(0,0,0),(0,0,0),(0,1,0)]` then A is ____________.

A square matrix A = [a_ij]_nxn is called a diagonal matrix if a_ij = 0 for ____________.

If `[("a","b"),("c", "-a")]`is a square root of the 2 x 2 identity matrix, then a, b, c satisfy the relation ____________.

If k be an integer, then `lim_("x" -> "k") ("x" - ["x"])` ____________.

If A is a square matrix, then A – A’ is a ____________.

For any square matrix A, AA^T is a ____________.