Science (English Medium) Class 11 - CBSE Question Bank Solutions

If secx cos5x + 1 = 0, where 0 < x ≤ `pi/2`, then find the value of x.

The equation of the circle circumscribing the triangle whose sides are the lines y = x + 2, 3y = 4x, 2y = 3x is ______.

Equation of a circle which passes through (3, 6) and touches the axes is ______.

Equation of the circle with centre on the y-axis and passing through the origin and the point (2, 3) is ______.

The equation of a circle with origin as centre and passing through the vertices of an equilateral triangle whose median is of length 3a is ______.

`lim_(n -> oo) (1 + 2 + 3 + ... + n)/n^2`, n ∈ N, is equal to ______.

Find ‘n’ if `lim_(x -> 2) (x^n - 2^n)/(x - 2)` = 80, x ∈ N

If `f(x) = (x^n - a^n)/(x - a)` for some constant, a, then f'(a) is equal to ______.

Determine the mean and standard deviation for the following distribution:

State whether the following pairs of sets are disjoint.

{1, 2, 3, 4} and {x : x is a natural number and 4 ≤ x ≤ 6}

State whether the following pairs of sets are disjoint.

{a, e, i, o, u} and {c, d, e, f}

State whether the following pairs of sets are disjoint.

{x : x is an even integer} and {x : x is an odd integer}

State whether the following statement is true or false. Justify your answer.

{2, 3, 4, 5} and {3, 6} are disjoint sets.

State whether the following statement is true or false. Justify your answer.

{a, e, i, o, u } and {a, b, c, d} are disjoint sets.

State whether the following statement is true or false. Justify your answer.

{2, 6, 10, 14} and {3, 7, 11, 15} are disjoint sets.

State whether the following statement is true or false. Justify your answer.

{2, 6, 10} and {3, 7, 11} are disjoint sets.

\[\cap\] If A and B are two disjoint sets, then \[n \left( A \cup B \right)\]is equal to 

Prove that:  \[\sqrt{\frac{1 - \cos 2x}{1 + \cos 2x}} = \tan x\]

Prove that:  \[\frac{\sin 2x}{1 - \cos 2x} = cot x\]

Prove that:  \[\frac{\sin 2x}{1 + \cos 2x} = \tan x\]