Trigonometry Questions (1127)

If \(0 \leq \theta \leq 2\pi\) and \(2\sin^2 \theta - 5\sin \theta + 2 > 0\), then find the range of \(\theta\).
If \(\sum_{m=1}^{6} \csc\left(\alpha + (m-1)\dfrac{\pi}{4}\right)\csc\left(\alpha + \dfrac{m\pi}{4}\right) = 4\sqrt{2}\), where \(\alpha \in (0, \pi)\) then \(\alpha\) can be:
If \(x + \sin y = 2014\) and \(x + 2014\cos y = 2013\), where \(0 \le y \le \frac{\pi}{2}\), then find the value of \([x+y] - 2005\) (where \([\cdot]\) denotes greatest integer function).
If \(1 - \frac{\cos^2 A}{a^2} - 1 - \frac{\cos^2 B}{b^2} = \frac{2}{r_2} - \frac{2}{r_3}\), then the triangle is
The number of solutions of the equation \(|\cot x| = \cot x + \frac{1}{\sin x}\), \(0
If |sin x + cos x| = |sin x| + |cos x|, x ∈ [0, 2π] then the solution set is
Let \(\theta = \sin^{-1}\left(\dfrac{3\sin 2\alpha}{5 + 4\cos 2\alpha}\right)\). Then \(\tan^{-1} x = \dfrac{\theta}{2}\) where \(x\) equals:
If \cos^{-1}\left(\frac{1-x^2}{1+x^2}\right) , then
We have tan(15°) + tan(30°) = –p and tan(15°) + tan(30°) = –p. Given that tan(45°) = 1, find the value of (2 + q – p) where q – p = 1.
Find the value of \(\cos\left(\frac{2\pi}{7}\right)\cos\left(\frac{4\pi}{7}\right)\cos\left(\frac{8\pi}{7}\right)\)
Given \(f_k(x) = \dfrac{1}{k}(\sin^k x + \cos^k x)\), find the value of \(f_4(x) - f_6(x)\).
A vertical tower subtends an angle of $60°$ at a point on the same level as the foot of the tower. On moving $100$ m further from the first point in line with the tower, it subtends an angle of $30°$ at the point. If the height of the tower is $H$ m, then the value of $\frac{H}{\sqrt{3}}$ (in meters) is
If \(\frac{\cos(\alpha+\gamma)}{\cos(\alpha-\gamma)} = \cos 2\beta\) then \(\tan\alpha\), \(\tan\beta\) and \(\tan\gamma\) are in
The value of \(\sin\left(\frac{\pi}{14}\right)\sin\left(\frac{3\pi}{14}\right)\sin\left(\frac{5\pi}{14}\right)\) is
The number of solutions of the equation \(e^{\sin x} - e^{-\sin x} = 4\) is
Let a, b, c be three non-zero real numbers such that the equation acosx + 2bsinx = c, x ∈ [−π/2, π/2], has two distinct real roots α and β with α + β = π/3. Then, the value of b/a is __________________________.
Let $\alpha$ and $\beta$ respectively be the maximum and minimum values of the function $f(\theta)=4\left(\sin^4\!\left(\dfrac{7\pi}{2}-\theta\right)+\sin^4(11\pi+\theta)\right)-2\left(\sin^6\!\left(\dfrac{3\pi}{2}-\theta\right)+\sin^6(9\pi-\theta)\right)$, $\theta\in\mathbb{R}$. Then $\alpha+2\beta$ is equal to:
For \(x \in (0, \pi)\), the equation \(\sin x + 2 \sin 2x - \sin 3x = \frac{3}{5}\) has
If PQ be a vertical tower subtending angles α, β and γ at the points A, B and C respectively on the line in the horizontal plane through the foot D of tower and on the same side of it, then BC cot α - CA cot β + AB cot γ is equal to
A regular polygon of \(n\) sides is inscribed in a circle of radius \(R\) and another regular polygon of \(n\) sides is circumscribed about a circle of radius \(r\), where \(\theta = \dfrac{\pi}{n}\). Then \(r + R\) equals:
The value of the expression \(\dfrac{\sin^2\dfrac{2\pi}{7} + \sin^2\dfrac{4\pi}{7} + \sin^2\dfrac{\pi}{7}}{\sin^2\dfrac{\pi}{7} + \sin^2\dfrac{2\pi}{7} + \sin^2\dfrac{4\pi}{7}}\) is equal to:
If $x = y = z$, $x, y, z$ are in AP, and $\tan^{-1}x$, $\tan^{-1}y$, $\tan^{-1}z$ are also in AP, find the relationship between $x$ and $z$.
If \sin^4 x + \cos^4 x = \sin x \cos x, then x is
Let \(2\sin^2 x + 3\sin x - 2 \geq 0\) and \(x^2 - x - 2
Range of \(f(x)=\cot^{-1}(\log_e(1-x^2))\) is:
Find the value of \(16(\sin^2 18^\circ + \sin^2 36^\circ + \sin^2 54^\circ + \sin^2 72^\circ)\).
The value of \cos 12° + \cos 84° + \cos 156° + \cos 132°\ is
173. If \(\cos x + \cos^2 x = 1\). Let \(E = \sin^{12} x + 3\sin^{10} x + 3\sin^8 x + \sin^6 x + 2\), then the value of \(\log_{\tan\frac{\pi}{3}} E\) is:
Consider a triangular plot ABC with sides AB = 7 m, BC = 5 m and CA = 6 m. A vertical lamp-post at the mid-point D of AC subtends an angle 30° at B. The height (in m) of the lamp-post is
$96\cos\dfrac{\pi}{33}\cos\dfrac{2\pi}{33}\cos\dfrac{4\pi}{33}\cos\dfrac{8\pi}{33}\cos\dfrac{16\pi}{33}$ is equal to
The value of \( \tan^{-1}\left(\dfrac{1}{4}\right) + \tan^{-1}\left(\dfrac{2}{9}\right) \) is:
A ladder 5 m long leans against a vertical wall. The bottom of the ladder is 3 m from the wall. If the bottom of the ladder is pulled 1 m farther from the wall, how much does the top of the ladder slide down the wall
In \(\triangle ABC\), if incircle touches the sides \(AB\), \(BC\) and \(CA\) at \(P\), \(Q\) and \(R\) respectively and \(s - a = 3\), \(s - b = 5\) and \(s - c = 7\), then area of the quadrilateral \(QCRI\) is, where \(I\) is incentre of \(\triangle ABC\):[Note: Symbols used have usual meaning in \(\triangle ABC\).]
The value of \(\cos^2 x\left(\frac{1}{3} + x\right) - \cos x \cdot \cos\left(\frac{2}{3} + x\right)\) is
Let \(0 \leq \theta \leq 2\pi\) and \(x = |\cos\theta + 1| + |\cos\theta - 1| + |\cos\theta - 2| + |\cos\theta - 3|\), then product of the maximum and minimum values of \(x\) is:
If sec x cos 5x + 1 = 0, where 0
If $P$ and $Q$ are the circumcentre and orthocentre of $\triangle ABC$, then $\overrightarrow{PA}+\overrightarrow{PB}+\overrightarrow{PC}$ is equal to
\(\sec^2 \theta = \frac{4xy}{(x+y)^2}\) is true if and only if
Let the plane $x+3y-2z+6=0$ meet the coordinate axes at $A$, $B$, $C$. If the orthocentre of $\triangle ABC$ is $\left(\alpha,\beta,\dfrac{6}{7}\right)$, then $98(\alpha+\beta)^2$ is equal to __________.
$\angle PQS = 90° = \angle PRS = 90°$
A number \(k\) is such that \(\tan[\arctan(2) + \arctan(20k)] = k\). The sum of all possible values of \(k\) is ______.
Two poles standing on a horizontal ground are of heights 5 m and 10 m, respectively. The line joining their tops makes an angle of 15° with ground. Then, the distance (in m) between the poles is
The number of points of intersection of \(2y = 1\) and \(y = \cos x\) in \(-\frac{\pi}{2} \leq x \leq \frac{\pi}{2}\) is
The period of \(\sin^2\theta\) is:
Let period of \(f(x) = \frac{|\sin x| - |\cos x|}{|\sin x + \cos x|}\) is l, then [4l] is equal to __________ where []× denotes greatest integer function.
Let $C(\alpha,\beta)$ be the circumcentre of the triangle formed by the lines $4x+3y=69$, $4y-3x=17$, and $x+7y=61$. Then $(\alpha-\beta)^2+\alpha+\beta$ is equal to
Find $\tan 20° - 33\tan^3 20° + 27\tan^2 20° - 4 = $
A flag-staff of 5 meters high stands on a building of 25 meters height. For an observer at a height of 30 meters, the flag-staff and the building subtend equal angles. The distance of the observer from the top of the flag-staff is
A tower subtends angles $\alpha$, $2\alpha$ and $3\alpha$, respectively, at points $A$, $B$ and $C$ all lying on a horizontal line through the foot of the tower. If $\frac{AB}{BC} = 1 + p \cos p\alpha$, then the value of $p$ is
Area of circumcircle of quadrilateral PLOM is