Finding roots of this trig eqn

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In summary, the problem is asking for the possible values of x that satisfy the equation [sinx]+[√2 cosx]=-3, where x belongs to the interval [0,2∏]. After some trial and error, it is determined that the answer is either (5∏/4,2∏) or (∏,5∏/4). However, there may be a more efficient method for solving this problem.
  • #1
utkarshakash
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Homework Statement


If [sinx]+[√2 cosx]=-3, x belongs to [0,2∏] (where [.] denotes the greatest integer function) then x belongs to
1)[5∏/4,2∏]
2)(5∏/4,2∏)
3)(∏,5∏/4)
4)[∏,5∏/4]

The Attempt at a Solution



If I put x=5∏/4, LHS=-2 which does not satisfy. 2∏ and ∏ also does not satisfy.So the answer must be either 2) or 3). Is there any better way other than putting the values one by one and checking?
 
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  • #2
utkarshakash said:

Homework Statement


If [sinx]+[√2 cosx]=-3, x belongs to [0,2∏] (where [.] denotes the greatest integer function) then x belongs to
1)[5∏/4,2∏]
2)(5∏/4,2∏)
3)(∏,5∏/4)
4)[∏,5∏/4]

The Attempt at a Solution



If I put x=5∏/4, LHS=-2 which does not satisfy. 2∏ and ∏ also does not satisfy.So the answer must be either 2) or 3). Is there any better way other than putting the values one by one and checking?
What are the lowest possible values of the two terms on the left? How can they add to -3?
 
  • #3
haruspex said:
What are the lowest possible values of the two terms on the left? How can they add to -3?

That was helpful. Thanks!
 

Related to Finding roots of this trig eqn

1. What is meant by "finding roots" in a trigonometric equation?

Finding roots of a trigonometric equation refers to determining the values of the variable that make the equation true. In other words, it is the process of finding the solutions or values of the variable that satisfy the given trigonometric equation.

2. How do I find the roots of a trigonometric equation?

The process of finding roots of a trigonometric equation depends on the specific equation and may involve using algebraic manipulation, trigonometric identities, and properties of trigonometric functions. It may also require the use of a calculator or graphing software to approximate the solutions.

3. Can a trigonometric equation have more than one root?

Yes, a trigonometric equation can have multiple roots or solutions. This is because trigonometric functions are periodic, meaning they repeat their values after a certain interval. Therefore, there can be multiple values of the variable that satisfy the equation.

4. How do I know if my solution is an extraneous root?

An extraneous root is a solution that does not satisfy the original equation. This can occur when the equation has been manipulated in a way that introduces additional solutions. It is important to always check the solutions in the original equation to ensure they are valid.

5. Are there any special cases to consider when finding roots of trigonometric equations?

Yes, there are a few special cases to consider when finding roots of trigonometric equations. These include equations with multiple angles, equations involving inverse trigonometric functions, and equations with restrictions on the domain. It is important to be familiar with these cases and their solutions when solving trigonometric equations.

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