मराठी

State whether the statement is True or False? Also give justification. One value of θ which satisfies the equation sin4θ - 2sin2θ - 1 lies between 0 and 2π.

Advertisements
Advertisements

प्रश्न

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

One value of θ which satisfies the equation sin4θ - 2sin2θ - 1 lies between 0 and 2π.

पर्याय

  • True

  • False

MCQ
चूक किंवा बरोबर
Advertisements

उत्तर

This statement is False.

Explanation:

Given equation is sin4θ – 2sin2θ – 1 = 0

sin2θ = `(-(-2) +- sqrt((-2)^2 - 4 xx 1 xx -1))/(2 xx 1)`

= `(2 +-  sqrt(4 + 4))/2`

= `(2 +-  sqrt(8))/2`

= `(2 +-  2sqrt(2))/2`

= `1 +- sqrt(2)`

∴ sin2θ = `(1 + sqrt(2))` or `(1 - sqrt(2))`

⇒ – 1 ≤ sin θ ≤ 1

⇒ sin2θ ≤ 1 but sin2θ = `(1 + sqrt(2))` or `(1 - sqrt(2))`

Which is not possible.

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 3: Trigonometric Functions - Exercise [पृष्ठ ६०]

APPEARS IN

एनसीईआरटी एक्झांप्लर Mathematics [English] Class 11
पाठ 3 Trigonometric Functions
Exercise | Q 72 | पृष्ठ ६०

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

Find the radian measure corresponding to the following degree measure:

– 47° 30'


Find the radian measure corresponding to the following degree measure:

240°


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

`(5pi)/3`


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

`(7pi)/6`


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`)


In a circle of diameter 40 cm, the length of a chord is 20 cm. Find the length of minor arc of the chord.


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

10 cm


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:
\[\frac{9\pi}{5}\]


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


Find the degree measure corresponding to the following radian measure: 
(−3)c


Find the degree measure corresponding to the following radian measure: 
 11c


Find the degree measure corresponding to the following radian measure: 
 1c


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


Find the radian measure corresponding to the following degree measure: 35°


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


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


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 angles of a triangle are in A.P. and the number of degrees in the least angle is to the number of degrees in the mean angle as 1 : 120. 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.

 

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


At 3:40, the hour and minute hands of a clock are inclined at


A circular wire of radius 3 cm is cut and bent so as to lie along the circumference of a hoop whose radius is 48 cm. Find the angle in degrees which is subtended at the centre of hoop.


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


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


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


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


The value of cos1° cos2° cos3° ... cos179° is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×