MCQ
If $(2\cos x - 1)(3 + 2\cos x) = 0,\,0 \le x \le 2\pi $, then $x = $
  • A
    $\frac{\pi }{3}$
  • $\frac{\pi }{3},\frac{{5\pi }}{3}$
  • C
    $\frac{\pi }{2},\frac{{5\pi }}{3},{\cos ^{ - 1}}\left( { - \frac{3}{2}} \right)$
  • D
    $\frac{{5\pi }}{3}$

Answer

Correct option: B.
$\frac{\pi }{3},\frac{{5\pi }}{3}$
b
(b) $(2\cos x - 1)\,\,(3 + 2\cos x) = 0$

Then $\cos x = \frac{1}{2}{\rm{ as}}\,{\rm{ }}\cos x \ne \frac{{ - 3}}{2}$

$ \Rightarrow $ $x = 2n\pi \pm \frac{\pi }{3};\,\,\left\{ \begin{array}{l}{\rm{ \,for \,\,}}n = 0,\,\,x = \frac{\pi }{3},\,\frac{{5\pi }}{3}\\{\rm{ \,for\,\, }}n = 1,\,\,x = \frac{{5\pi }}{3}\end{array} \right\}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Consider the lines $L_1$ and $L_2$ defined by

$L _1: x \sqrt{2}+ y -1=0$ and $L _2: x \sqrt{2}- y +1=0$

For a fixed constant $\lambda$, let $C$ be the locus of a point $P$ such that the product of the distance of $P$ from $L_1$ and the distance of $P$ from $L_2$ is $\lambda^2$. The line $y=2 x+1$ meets $C$ at two points $R$ and $S$, where the distance between $R$ and $S$ is $\sqrt{270}$.

Let the perpendicular bisector of $RS$ meet $C$ at two distinct points $R ^{\prime}$ and $S ^{\prime}$. Let $D$ be the square of the distance between $R ^{\prime}$ and $S ^{\prime}$.

($1$) The value of $\lambda^2$ is

($2$) The value of $D$ is

Which of the following is a statement.
The centroid of the triangle formed by joining the feet of the normals drawn from any point to the parabola ${y^2} = 4ax$, lies on
Let $a \in R$ and let $\alpha, \beta$ be the roots of the equation $x^2+60^{\frac{1}{4}} x+a=0$. If $\alpha^4+\beta^4=-30$, then the product of all possible values of $a$ is $......$
Number of integral solutions satisfy inequality $|\text{x-3}|-|2\text{x}+5|\geq|\text{x}+8|$
If $x$ be real, then the minimum value of ${x^2} - 8x + 17$ is
If $ A, B, C $ are represented by $3 + 4i,$ $5 - 2i$, $ - 1 + 16i$, then $A, B, C$  are
The sum of the first $20$  terms of the series  $1 + \frac{3}{2} + \frac{7}{4} + \frac{{15}}{8} + \frac{{31}}{{16}} + ...$ is?
A rectangular hyperbola of latus rectum $2$ units passes through $(0, 0)$ and has $(1, 0)$ as its one focus. The other focus lies on the curve -
If $\tan \theta = \frac{{ - 4}}{3},$ then $\sin \theta = $