हिंदी

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. - Mathematics

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.

विकल्प

  • True

  • False

MCQ
सत्य या असत्य
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
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 3: Trigonometric Functions - Exercise [पृष्ठ ६०]

APPEARS IN

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

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

Find the radian measure corresponding to the following degree measure:

25°


Find the radian measure corresponding to the following degree measure:

240°


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

15 cm


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


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


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


One angle of a triangle \[\frac{2}{3}\] x grades and another is \[\frac{3}{2}\] x degrees while the third is \[\frac{\pi x}{75}\] radians. Express all the angles in degrees.


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 octagon.


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


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


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.


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?

 

The angle between the minute and hour hands of a clock at 8:30 is


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


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


A circular wire of radius 7 cm is cut and bent again into an arc of a circle of radius 12 cm. The angle subtended by the arc at the centre 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

 

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.


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 inequality `2^sintheta + 2^costheta ≥ 2^(1/sqrt(2))` holds for all real values of θ” 


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


Which of the following is correct?

[Hint: 1 radian = `180^circ/pi = 57^circ30^'` approx]


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

Sin10° is greater than cos10°


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×