हिंदी

Solve the Following Equation: Sin 2 X − Cos X = 1 4 - Mathematics

Advertisements
Advertisements

प्रश्न

Solve the following equation:
\[\sin^2 x - \cos x = \frac{1}{4}\]

योग
Advertisements

उत्तर

\[\sin^2 x - \cos x = \frac{1}{4}\]
\[\Rightarrow 1 - \cos^2 x - \cos x = \frac{1}{4}\]
\[ \Rightarrow 4 - 4 \cos^2 x - 4 \cos x = 1\]
\[ \Rightarrow 4 \cos^2 x + 4 \cos x - 3 = 0\]
\[ \Rightarrow 4 \cos^2 x + 6 \cos x - 2 \cos x - 3 = 0\]
\[ \Rightarrow 2 \cos x(2 \cos x + 3) - 1(2 \cos x + 3) = 0\]
\[ \Rightarrow (2 \cos x + 3) (2 \cos x - 1) = 0\]
\[\Rightarrow (2 \cos x - 1) = 0\] or
\[2 \cos x + 3 = 0\]
\[\Rightarrow \cos x = \frac{1}{2}\] or
\[\cos x = - \frac{3}{2}\] is not possible.
\[\therefore \cos x = \frac{1}{2} \]
\[ \Rightarrow \cos x = \cos\frac{\pi}{3} \]
\[ \Rightarrow x = 2n\pi \pm \frac{\pi}{3}, n \in Z\]
shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 11: Trigonometric equations - Exercise 11.1 [पृष्ठ २२]

APPEARS IN

आरडी शर्मा Mathematics [English] Class 11
अध्याय 11 Trigonometric equations
Exercise 11.1 | Q 3.1 | पृष्ठ २२

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

Find the general solution of cosec x = –2


Find the general solution for each of the following equations sec2 2x = 1– tan 2x


If \[\tan x = \frac{a}{b},\] show that

\[\frac{a \sin x - b \cos x}{a \sin x + b \cos x} = \frac{a^2 - b^2}{a^2 + b^2}\]

If \[cosec x - \sin x = a^3 , \sec x - \cos x = b^3\], then prove that \[a^2 b^2 \left( a^2 + b^2 \right) = 1\]


Prove the:
\[ \sqrt{\frac{1 - \sin x}{1 + \sin x}} + \sqrt{\frac{1 + \sin x}{1 - \sin x}} = - \frac{2}{\cos x},\text{ where }\frac{\pi}{2} < x < \pi\]


If \[T_n = \sin^n x + \cos^n x\], prove that  \[2 T_6 - 3 T_4 + 1 = 0\]


Prove that:  tan 225° cot 405° + tan 765° cot 675° = 0


Prove that:
\[\frac{\cos (2\pi + x) cosec (2\pi + x) \tan (\pi/2 + x)}{\sec(\pi/2 + x)\cos x \cot(\pi + x)} = 1\]

 


Prove that

\[\frac{cosec(90^\circ + x) + \cot(450^\circ + x)}{cosec(90^\circ - x) + \tan(180^\circ - x)} + \frac{\tan(180^\circ + x) + \sec(180^\circ - x)}{\tan(360^\circ + x) - \sec( - x)} = 2\]

 


Prove that:
\[\sec\left( \frac{3\pi}{2} - x \right)\sec\left( x - \frac{5\pi}{2} \right) + \tan\left( \frac{5\pi}{2} + x \right)\tan\left( x - \frac{3\pi}{2} \right) = - 1 .\]


Find x from the following equations:
\[cosec\left( \frac{\pi}{2} + \theta \right) + x \cos \theta \cot\left( \frac{\pi}{2} + \theta \right) = \sin\left( \frac{\pi}{2} + \theta \right)\]


Prove that:

\[\tan\frac{5\pi}{4}\cot\frac{9\pi}{4} + \tan\frac{17\pi}{4}\cot\frac{15\pi}{4} = 0\]

 


If tan x = \[x - \frac{1}{4x}\], then sec x − tan x is equal to


If \[\frac{\pi}{2} < x < \frac{3\pi}{2},\text{ then }\sqrt{\frac{1 - \sin x}{1 + \sin x}}\] is equal to

 


The value of sin25° + sin210° + sin215° + ... + sin285° + sin290° is


sin2 π/18 + sin2 π/9 + sin2 7π/18 + sin2 4π/9 =


If tan A + cot A = 4, then tan4 A + cot4 A is equal to


If x sin 45° cos2 60° = \[\frac{\tan^2 60^\circ cosec30^\circ}{\sec45^\circ \cot^{2^\circ} 30^\circ}\], then x =

 

Which of the following is incorrect?


Find the general solution of the following equation:

\[\sin 9x = \sin x\]

Find the general solution of the following equation:

\[\sin 2x = \cos 3x\]

Find the general solution of the following equation:

\[\tan 2x \tan x = 1\]

Solve the following equation:

\[\cos x + \sin x = \cos 2x + \sin 2x\]

Solve the following equation:

\[\sin 3x - \sin x = 4 \cos^2 x - 2\]

Solve the following equation:

\[\sin 2x - \sin 4x + \sin 6x = 0\]

Solve the following equation:

\[\tan x + \tan 2x + \tan 3x = 0\]

Solve the following equation:

\[\tan 3x + \tan x = 2\tan 2x\]

Solve the following equation:
\[2^{\sin^2 x} + 2^{\cos^2 x} = 2\sqrt{2}\]


Write the number of solutions of the equation tan x + sec x = 2 cos x in the interval [0, 2π].


Write the number of points of intersection of the curves

\[2y = 1\] and \[y = \cos x, 0 \leq x \leq 2\pi\].
 

The general solution of the equation \[7 \cos^2 x + 3 \sin^2 x = 4\] is


If \[4 \sin^2 x = 1\], then the values of x are

 


A value of x satisfying \[\cos x + \sqrt{3} \sin x = 2\] is

 

Find the principal solution and general solution of the following:
tan θ = `- 1/sqrt(3)`


Solve the following equations for which solution lies in the interval 0° ≤ θ < 360°

2 cos2x + 1 = – 3 cos x


Solve the following equations:
sin 5x − sin x = cos 3


Solve the following equations:
`sin theta + sqrt(3) cos theta` = 1


Solve the following equations:
2cos 2x – 7 cos x + 3 = 0


Choose the correct alternative:
If f(θ) = |sin θ| + |cos θ| , θ ∈ R, then f(θ) is in the interval


If sin θ and cos θ are the roots of the equation ax2 – bx + c = 0, then a, b and c satisfy the relation ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×