English

Find the value of 3 cosec 20° – sec 20°

Advertisements
Advertisements

Question

Find the value of `sqrt(3)` cosec 20° – sec 20°

Sum
Advertisements

Solution

We have

`sqrt(3)` cosec 20° – sec 20° = `sqrt(3)/(sin20^circ) - 1/(cos20^circ)`

= `(sqrt(3)  cos 20^circ -  sin 20^circ)/(sin 20^circ cos 20^circ)`

= `4((sqrt(3)/2 cos 20^circ - 1/2 sin 20^circ)/(2sin 20^circ cos 20^circ))`

= `4((sin60^circ cos20^circ - cos60^circ sin20^circ)/sin40^circ)`   

= `4((sin(60^circ - 20^circ))/(sin 40^circ))` 

= 4  

shaalaa.com
  Is there an error in this question or solution?
Chapter 3: Trigonometric Functions - Solved Examples [Page 40]

APPEARS IN

NCERT Exemplar Mathematics Exemplar [English] Class 11
Chapter 3 Trigonometric Functions
Solved Examples | Q 3 | Page 40

Video TutorialsVIEW ALL [1]

RELATED QUESTIONS

Find the radian measure corresponding to the following degree measure:

520°


Find the degree measure corresponding to the following radian measure `(use  pi = 22/7)`

`11/16`


Find the degree measures corresponding to the following radian measures (Use `pi = 22/7`)

`(5pi)/3`


A wheel makes 360 revolutions in one minute. Through how many radians does it turn in one second?


Find the degree measure of the angle subtended at the centre of a circle of radius 100 cm by an arc of length 22 cm

(Use `pi = 22/7`)


If in two circles, arcs of the same length subtend angles 60° and 75° at the centre, find the ratio of their radii.


Find the angle in radian through which a pendulum swings if its length is 75 cm and the tip describes an arc of length

21 cm


Find the degree measure corresponding to the following radian measure:
\[- \frac{5\pi}{6}\]


Find the degree measure corresponding to the following radian measure:
\[\left( \frac{18\pi}{5} \right)\]


Find the radian measure corresponding to the following degree measure: −56°


Find the radian measure corresponding to the following degree measure: 135°


Find the radian measure corresponding to the following degree measure: −300°


Find the radian measure corresponding to the following degree measure: 125° 30'


Find the magnitude, in radians and degrees, of the interior angle of a regular octagon.


Let the angles of the quadrilateral be \[\left( a - 3d \right)^\circ, \left( a - d \right)^\circ, \left( a + d \right)^\circ \text{ and }\left( a + 3d \right)^\circ\]
We know: \[a - 3d + a - d + a + d + a - 2d = 360\]
\[ \Rightarrow 4a = 360\]
\[ \Rightarrow a = 90\]
We have:
Greatest angle = 120°
Now,
\[a + 3d = 120\]
\[ \Rightarrow 90 + 3d = 120\]
\[ \Rightarrow 3d = 30\]
\[ \Rightarrow d = 10\]
Hence,
\[\left( a - 3d \right)^\circ, \left( a - d \right)^\circ, \left( a + d \right)^\circ\text{ and }\left( a + 3d \right)^\circ\] are

\[60^\circ, 80^\circ, 100^\circ\text{ and }120^\circ\], respectively.
Angles of the quadrilateral in radians =
\[\left( 60 \times \frac{\pi}{180} \right), \left( 80 \times \frac{\pi}{180} \right) , \left( 100 \times \frac{\pi}{180} \right) \text{ and }\left( 120 \times \frac{\pi}{180} \right)\]
\[\frac{\pi}{3}, \frac{4\pi}{9}, \frac{5\pi}{9}\text{ and } \frac{2\pi}{3}\]
 

 


The angle in one regular polygon is to that in another as 3 : 2 and the number of sides in first is twice that in the second. Determine the number of sides of two polygons.

 

The angles of a triangle are in A.P. such that the greatest is 5 times the least. Find the angles in radians.


The number of sides of two regular polygons are as 5 : 4 and the difference between their angles is 9°. Find the number of sides of the polygons.

 

Find the length which at a distance of 5280 m will subtend an angle of 1' at the eye.

 

A wheel makes 360 revolutions per minute. Through how many radians does it turn in 1 second?

 

Find the distance from the eye at which a coin of 2 cm diameter should be held so as to conceal the full moon whose angular diameter is 31'.


Find the diameter of the sun in km supposing that it subtends an angle of 32' at the eye of an observer. Given that the distance of the sun is 91 × 106 km.

 

Find the degree measure of the angle subtended at the centre of a circle of radius 100 cm by an arc of length 22 cm.


If the arcs of the same length in two circles subtend angles 65° and 110° at the centre, than the ratio of the radii of the circles is


If OP makes 4 revolutions in one second, the angular velocity in radians per second is


The radius of the circle whose arc of length 15 π cm makes an angle of \[\frac{3\pi}{4}\]  radian at the centre is

 

If θ lies in the second quadrant, then show that `sqrt((1 - sin theta)/(1 + sin theta)) + sqrt((1 + sin theta)/(1 - sin theta))` = −2sec θ


Find the value of tan 9° – tan 27° – tan 63° + tan 81°


Prove that `(sec8 theta - 1)/(sec4 theta - 1) = (tan8 theta)/(tan2 theta)`


If tan θ = `(-4)/3`, then sin θ is ______.


The value of tan1° tan2° tan3° ... tan89° is ______.


State whether the statement is True or False? Also give justification.

`cos  (2pi)/15 cos  (4pi)/15 cos  (8pi)/15 cos  (16pi)/15 = 1/16`


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×