Home
Class 12
MATHS
If number of solution and sum of solutio...

If number of solution and sum of solution of the equation ` 3sin^(2)x-7sinx +2=0, x in [0,2pi]` are respectively N and S and ` f_(n)(theta)=sin^(n)theta +cos^(n) theta`. On the basis of above information , answer the following questions.
Value of N is

A

1

B

2

C

3

D

4

Text Solution

AI Generated Solution

The correct Answer is:
To find the value of \( N \) (the number of solutions) for the equation \( 3\sin^2 x - 7\sin x + 2 = 0 \) in the interval \( x \in [0, 2\pi] \), we will follow these steps: ### Step 1: Rewrite the equation The given equation is: \[ 3\sin^2 x - 7\sin x + 2 = 0 \] Let \( y = \sin x \). Then the equation becomes: \[ 3y^2 - 7y + 2 = 0 \] ### Step 2: Factor the quadratic equation We need to factor the quadratic equation \( 3y^2 - 7y + 2 \). We can look for two numbers that multiply to \( 3 \times 2 = 6 \) and add up to \( -7 \). The numbers are \( -6 \) and \( -1 \). Thus, we can write: \[ 3y^2 - 6y - y + 2 = 0 \] Grouping the terms: \[ 3y(y - 2) - 1(y - 2) = 0 \] Factoring out \( (y - 2) \): \[ (3y - 1)(y - 2) = 0 \] ### Step 3: Solve for \( y \) Setting each factor to zero gives us: 1. \( 3y - 1 = 0 \) → \( y = \frac{1}{3} \) 2. \( y - 2 = 0 \) → \( y = 2 \) ### Step 4: Analyze the solutions The value \( y = 2 \) is not valid because the sine function only takes values in the range \([-1, 1]\). Thus, we only consider \( y = \frac{1}{3} \). ### Step 5: Find the corresponding \( x \) values Now we need to find \( x \) such that: \[ \sin x = \frac{1}{3} \] In the interval \( [0, 2\pi] \), the sine function is positive in the first and second quadrants. Therefore, we will have two solutions: 1. \( x = \arcsin\left(\frac{1}{3}\right) \) 2. \( x = \pi - \arcsin\left(\frac{1}{3}\right) \) ### Step 6: Count the number of solutions Thus, the number of solutions \( N \) is: \[ N = 2 \] ### Final Answer The value of \( N \) is \( 2 \). ---
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • TRIGONOMETRIC EQUATIONS AND INEQUATIONS

    ARIHANT MATHS ENGLISH|Exercise Exercise (Single Integer Answer Type Questions)|11 Videos
  • TRIGONOMETRIC EQUATIONS AND INEQUATIONS

    ARIHANT MATHS ENGLISH|Exercise Exercise (Statement I And Ii Type Questions)|6 Videos
  • TRIGONOMETRIC EQUATIONS AND INEQUATIONS

    ARIHANT MATHS ENGLISH|Exercise Exercise (More Than One Correct Option Type Questions)|25 Videos
  • THREE DIMENSIONAL COORDINATE SYSTEM

    ARIHANT MATHS ENGLISH|Exercise Three Dimensional Coordinate System Exercise 12 : Question Asked in Previous Years Exam|2 Videos
  • TRIGONOMETRIC FUNCTIONS AND IDENTITIES

    ARIHANT MATHS ENGLISH|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|19 Videos

Similar Questions

Explore conceptually related problems

If number of solution and sum of solution of the equation 3sin^(2)x-7sinx +2=0, x in [0,2pi] are respectively N and S and f_(n)(theta)=sin^(n)theta +cos^(n) theta . On the basis of above information , answer the following questions. If alpha is solution of equation 3sin^(2)x-7sinx+2=0, x in [0,2pi] , then the value of f_(4)(alpha) is

3sin^(2)x-7sin x +2=0, x in [0,(pi)/(2)] and f_(n)(theta)=sin^(n) theta + cos^(n) theta . On the basis of above information, the value of f_(4)(x) is:

3sin^(2)x-7sin x +2=0, x in [0,(pi)/(2)] and f_(n)(theta)=sin^(n) theta + cos^(n) theta . On the basis of above information, the value of ( sin 5 x + sin 4 x)/( 1+ 2 cos 3 x) is:

If m, n in N ( n> m ), then number of solutions of the equation n|sinx|=m|sinx| in [0, 2pi] is

The number of solutions of the equation sin 2 theta-2 cos theta +4 sin theta=4 in [0, 5pi] is equal to

The number of solution satisfying the equations tan 4theta=cot 5theta and sin 2theta=cos theta in [0,2pi] is

Solution of the equation sin (sqrt(1+sin 2 theta))= sin theta + cos theta is (n in Z)

If P_(n) = cos^(n)theta +sin^(n)theta , then P_(2) - P_(1) is equal to :

If theta in (pi//4, pi//2) and sum_(n=1)^(oo)(1)/(tan^(n)theta)=sin theta + cos theta , then the value of tan theta is

sin^2 n theta- sin^2 (n-1)theta= sin^2 theta where n is constant and n != 0,1