Trigonometry Questions - JEE

Given $\sin 3x = \cos 2x$, the number of solutions in $x \in \left(\dfrac{\pi}{2}, \pi\right)$ is:

If cos θ = 1/(x + 1/(2x)), then what is 2/(x² + 1/x) equal to

If cos 2θ = (√2 + 1) cos θ - 1/√2, then the value of θ is

A person standing on the bank of a river observes that the angle of elevation of the top of a tree on the opposite bank of the river is 60° and when he retires 40 metre away from the tree the angle of elevation becomes 30°. The breadth of the river is:

If a cos³ α + 3a cos α sin² α = m and a sin³ α + 3a cos² α sin α = n, then (m + n)^(2/3) + (m - n)^(2/3) is equal to

If P = cos(cos x) + sin(cos x), then the least and greatest value of P respectively are:

The perimeter of a △ABC is 48 cm and one side is 20 cm. Then remaining sides of △ABC must be greater than:

In triangle ABC, if ∠A = 30°, b = 10 and a = x, then the values of x for which there are 2 possible triangles is given by (All symbols have usual meaning in a triangle)

In triangle ABC, if AC = 8, BC = 7, and D lies between A and B such that AD = 2, BD = 4, then the length CD equals

In a triangle with one angle π/3, the lengths of the sides form an A.P. If the length of the greatest side is 7 cm, the radius of the circumcircle of the triangle is

The value of the expression \[\tan\!\left(\tan^{-1}\!\left(\frac{1}{2}\right)+\tan^{-1}\!\left(\frac{2}{9}\right)+\tan^{-1}\!\left(\frac{1}{8}\right)+\tan^{-1}\!\left(\frac{2}{25}\right)+\tan^{-1}\!\left(\frac{1}{18}\right)+\cdots\cdots\infty\right)\] is:

Determine the smallest positive value of x (in degrees) for which $\tan(x + 100°) = \tan(x + 50°) \cdot \tan x \cdot \tan(x - 50°)$.

Consider an obtuse angled triangle with sides 8 cm, 15 cm and $x$ cm (largest side being 15 cm). If $x$ is an integer, then find the number of possible triangles.

If a, b, c are the sides of a triangle, then the minimum value of $\dfrac{2a}{b+c-a} + \dfrac{2b}{c+a-b} + \dfrac{2c}{a+b-c}$ is

The general solution-set of the equation $\cos x + \cos 5x = 2$ is:

Given, $\frac{b+c}{11} = \frac{c+a}{12} = \frac{a+b}{13}$ for a triangle ABC with $\frac{\cos A}{\alpha} = \frac{\cos B}{\beta} = \frac{\cos C}{\gamma}$, then the ordered triad $(\alpha, \beta, \gamma)$ has a value

The equation $(\cos p - 1)x^2 + \cos p \cdot x + \sin p = 0$ where $x$ is a variable, has real roots. Then the interval of possible values of $p$ is

A train travelling on one of two intersecting railway lines, subtends at a certain station on the other line, an angle $\alpha$ when the front of the carriage reaches the junction and an angle $\beta$ when the end of the carriage reaches it. The two lines are inclined to each other at an angle $\theta$. Then $2\cot\theta$ is equal to

Consider a triangle ABC and let a, b and c denote the lengths of the sides opposite to vertices A, B and C, respectively. If a = 1, b = 3 and C = 60°, then $\sin^2 B$ is equal to

The number of solutions of $\sin 3x = \cos 2x$, in the interval $\left(\dfrac{\pi}{2}, \pi\right)$ is

An aeroplane flying at a height of $\sqrt{3}$ km above the ground passes vertically above another plane at an instant when the angles of elevation of the two planes from a point on the ground are $60°$ and $30°$ respectively. The distance (in km) between the two planes at that instant is:

If sin A / sin B = 5/2 and cos A / cos B = 3/2, where 0 , then

If 0 x x which satisfy the equation cos x + cos 2x + cos 3x + cos 4x = 0 is:

If $A(n) = (\sin 1) \times (\sin 2) \times \cdots \times \sin(n), \forall n \in \mathbb{N}$, then the number of elements in the set $A = \{f(1), f(2), \ldots, f(6)\}$ that are positive are

If $\tan(\alpha - \beta) = \dfrac{\sin(2\beta)}{3 - \cos(2\beta)}$, then $\tan\alpha = f(\beta)$. The value of $f\!\left(\dfrac{\pi}{3}\right)$ equals:

If x and y are non-zero real numbers satisfying xy(x2 − y2) = x2 + y2, then find the minimum value of x2 + y2.

The expression cos²(A - B) + cos² B - 2cos(A - B)cos A cos B is

Let x + y + z = θ and k = 2. If $\cos x + \cos y + \cos z = k\cos\theta$ and $\sin x + \sin y + \sin z = k\sin\theta$, find the value of $\cos(x+y) + \cos(y+z) + \cos(z+x)$.

If $A$, $B$, $C$ are in AP and $B = \frac{\pi}{4}$ then $\tan A \cdot \tan B \cdot \tan C =$ ______

Given that $\cos(\alpha + \beta) = \dfrac{4}{5}$ and $\sin(\alpha - \beta) = \dfrac{5}{13}$, where $\alpha + \beta \in \left[0, \dfrac{\pi}{2}\right]$ and $\alpha - \beta \in \left[0, \dfrac{\pi}{4}\right]$, then $\tan 2\alpha$ is equal to:

The sum of solutions in $(0, 2\pi)$ of the equation $\cos x \cos\!\left(\dfrac{\pi}{3} - x\right)\cos\!\left(\dfrac{\pi}{3} + x\right) = \dfrac{1}{4}$ is:

If $\cos 2\theta = \sin\alpha$ then the most general relation between $\theta$ and $\alpha$ is (where $n \in \mathbb{Z}$)

A tower $T_1$ of height 60 m is located exactly opposite to a tower $T_2$ of height 80 m on a straight road. From the top of $T_1$, if the angle of depression of the foot of $T_2$ is twice the angle of elevation of the top of $T_2$, then the width (in m) of the road between the feet of the towers $T_1$ and $T_2$ is

Paragraph (Questions 7-8): Let the incircle of $\triangle ABC$ touch sides $BC, CA, AB$ at $A_1, B_1, C_1$ respectively. The incircle of $\triangle A_1B_1C_1$ touches its sides $B_1C_1, C_1A_1, A_1B_1$ at $A_2, B_2, C_2$ respectively and so on.Find $\lim_{n \to \infty} \angle A_n$

If $\cos^2 x = t$, and the equation $5\left[\frac{1-t}{t} - t\right] = 2(2t-1) + 9$ is satisfied, then find the value of $\cos 4x$.

With the usual notation, in triangle ABC, if $\angle A + \angle B = 120°$, $a = \sqrt{3} + 1$ and $b = \sqrt{3} - 1$, then the ratio $\angle A : \angle B$ is

If in the pedal triangle DEF of an acute-angled triangle ABC, the sides are denoted by l, m, n, then l/(a²) + m/(b²) + n/(c²) is equal to

If $\tan\theta_1, \tan\theta_2, \tan\theta_3$ are the real roots of the equation $x^3 - (a+1)x^2 + (b-a)x - b = 0$, where $\theta_1 + \theta_2 + \theta_3 \in (0, \pi)$, then $\theta_1 + \theta_2 + \theta_3$ is equal to

AB is a vertical pole with B at the ground level and A at the top. A man finds that the angle of elevation of point A from a certain point C on the ground is 60°. He moves away from the pole along the line BC to a point D such that CD = 7 m. From D the angle of elevation of the point A is 45°. Then the height of the pole is

$3 \csc 20° - \sec 20°$ is equal to

The value of $\sqrt{3}\csc 20° - \sec 20°$ is equal to

The number of values of $x$ in $[0, 5\pi]$ satisfying the equation $3\sin^2 x - 7\sin x + 2 = 0$ is

Solution set of the inequality $(\cot^{-1}x)^2 - 5(\cot^{-1}x) + 6 > 0$ is

In triangle ABC, given a/sin A = 2√2/sin 30° = 4/sin C. Find angles C and A.

Two flagstaffs stand on a horizontal plane. A and B are two points on the line joining their feet and between them. The angles of elevation of the tops of the flagstaffs as seen from A are 30° and 60° and as seen from B are 60° and 45°. If AB is 30 m, the distance between the flagstaffs in metres is

If sin θ + cos θ = a and sin³ θ + cos³ θ = b, then the value of λ³ + μ³ + ν³ is, where λa + μb + νa = 0 and λ, μ, ν are independent of θ.

The value of expression $\frac{8}{1 + \tan(100°)}$ is equal to

If $\dfrac{\cos^248°-\sin^212°}{\sin^224°-\sin^26°}=\dfrac{\alpha+\beta\sqrt{5}}{2}$, where $\alpha,\beta\in\mathbb{N}$, then $\alpha+\beta$ is equal to _____.

If $a\sin\theta - b\cos\theta = -\sin 4\theta$ and $a\cos\theta + b\sin\theta = \frac{5}{2} - \frac{3}{2}\cos 4\theta$, then $(a+b)^{2/5} + (a-b)^{2/5}$ is _______.

If $\tan\left(142\frac{1}{2}°\right) = 2 + \sqrt{2} - \sqrt{\mu} - \sqrt{\lambda}$, then $\mu + \lambda =$

Trigonometry Questions (1127)