MCQ
$\int_0^{\pi /4} {[\sqrt {\tan x} + \sqrt {\cot x} ]\,dx} $ equals
  • A
    $\sqrt 2 \pi $
  • B
    $\frac{\pi }{2}$
  • $\frac{\pi }{{\sqrt 2 }}$
  • D
    $2\pi $

Answer

Correct option: C.
$\frac{\pi }{{\sqrt 2 }}$
c
(c) $I = \int_0^{\pi /4} {[\sqrt {\tan x} + \sqrt {\cot x]} } dx = \int_0^{\pi /4} {\frac{{\sin x + \cos x}}{{\sqrt {\sin x\cos x} }}dx} $

$ = \sqrt 2 \int_0^{\pi /4} {\frac{{\sin x + \cos x}}{{\sqrt {1 - {{(\sin x - \cos x)}^2}} }}dx} $

Put $\sin x - \cos x = t$; $(\cos x + \sin x)dx = dt$

$\therefore \,\,\,I = \sqrt 2 \int_{ - 1}^0 {\frac{{dt}}{{\sqrt {1 - {t^2}} }}} $

$I = \sqrt 2 [{\sin ^{ - 1}}t]_{ - 1}^0 = \sqrt 2 [0 - ( - \pi /2)] = \frac{\pi }{{\sqrt 2 }}$.

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

Choose the correct answer from the given four options:
let $\text{P}(\text{A})=\frac{7}{13},\text{P}(\text{B})=\frac{9}{13}$ and $\text{P}(\text{A}\cup\text{B})=\frac{4}{13}.$ Then $\text{P}\Big(\frac{\text{A'}}{\text{B}}\Big)$ is equal to:
On the interval $\left[ {\frac{{5\pi }}{3},\,\,\frac{{7\pi }}{4}} \right],$ the greatest value of the function $f(x) = \int_{5\pi /3}^x {(6\cos t - 2\sin t)\,dt = } $
Area bounded by parabola ${y^2} = x$ and straight line $2y = x$ is
The order and degree of the differential equation $\Big(1+3\frac{\text{dy}}{\text{dx}}\Big)^\frac{2}{3}=4\frac{\text{d}^3\text{y}}{\text{dx}^3}$ are:
If $P$ & $Q$ are two non-singular matrices of the same order such that $Q^r = I$ , for some integer $r > 1$ , then $P^{-1}Q^{r-1}P -P^{-1}Q^{-1}P$ is equal to (where $I$ is identity matrix and $O$ is null matrix)
Let a, b, c be positive real numbers. The following system of equations in x, y and z $\frac{\text{x}^2}{\text{a}^2}+\frac{\text{y}^2}{\text{b}^2}-\frac{\text{z}^2}{\text{c}^2}=1,$ $\frac{\text{x}^2}{\text{a}^2}-\frac{\text{y}^2}{\text{b}^2}+\frac{\text{z}^2}{\text{c}^2}=1,$ $-\frac{\text{x}^2}{\text{a}^2}+\frac{\text{y}^2}{\text{b}^2}+\frac{\text{z}^2}{\text{c}^2}=1$ has:
Thirty two persons $X_1, X_2, \ldots, X_{32}$ are randomly seated around a circular table at equal intervals. Two persons $X_i$ and $X_j$ are said to be within earshot of each other if there are at most three persons between them on the minor arc joining $X_i$ and $X_j$. The

probabiliky that $X_1$ and $X_3$ are within earshot of each other is, Here, $\left.{ }^n C_r=\frac{n !}{(n-r) ! r !}\right)$

$\int_0^a {x{{(2ax - {x^2})}^{\frac{3}{2}}}\,dx = } $
Choose the correct answer from the given four options : The maximum value of $\Big(\frac{1}{\text{x}}\Big)^\text{x}$ is :
A line with positive direction cosines passes through the point $P(2, -1, 2)$ and makes equal angles with the coordinate axes. The line meets the plane $2x + y + z = 9$ at point $Q$. The length of the line segment $PQ$ equals: