Trigonometric inequality problem.

In summary, the conversation discusses how to deduce that 0 ≤ x ≤ 10/9 for all values of x. Possible methods include sketching a graph and finding critical points to determine the maximum and minimum values. It is also suggested to multiply through by the denominator or prove that 1+sin(x)-(10/9)(5+4cos(x)) is always less than 0 to show the inequality.
  • #1
Michael_Light
113
0

Homework Statement



Deduce that 0 ≤
MSP154219h2f53c89aa97ch00001f2200631f7c6f1g.gif
≤ 10/9 for all values of x.

Homework Equations


The Attempt at a Solution



Is it possible to sketch a graph for
MSP154219h2f53c89aa97ch00001f2200631f7c6f1g.gif
? How?

Or is there any methods to find the max./min. value of
MSP154219h2f53c89aa97ch00001f2200631f7c6f1g.gif
?

Please enlighten me...
 
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  • #2
is the denominator ever zero or negative? if not try mutiplying through by it

or find the critical points to fiind max and min
 
  • #4
If you can prove [itex]1+sin(x)-\frac{10}{9}(5+4cos(x))[/itex] is always less than 0, you can get the less than part. If you think about the numerator, the greater than part also follows quickly.
 

FAQ: Trigonometric inequality problem.

1. What is a trigonometric inequality?

A trigonometric inequality is an expression that involves trigonometric functions (such as sine, cosine, and tangent) and inequality symbols (such as <, >, ≤, or ≥). It is used to compare the values of the trigonometric functions and determine when they are greater than, less than, or equal to each other.

2. How do you solve a trigonometric inequality?

To solve a trigonometric inequality, you need to use algebraic techniques to isolate the trigonometric function to one side of the inequality. Then, you can use the properties of the trigonometric functions to solve for the values that satisfy the inequality. Make sure to check your solutions to ensure they are valid.

3. What are the common mistakes when solving trigonometric inequalities?

One common mistake is forgetting to consider the restrictions on the trigonometric functions. For example, sine and cosine have a domain of [-1,1], so any solutions that fall outside of this range are invalid. Another mistake is not simplifying the expression before solving, which can lead to incorrect solutions.

4. Can you use a calculator to solve trigonometric inequalities?

Yes, you can use a calculator to solve trigonometric inequalities. However, it is important to be familiar with the properties of the trigonometric functions and understand how to use your calculator to solve equations and inequalities involving these functions.

5. What are some real-life applications of trigonometric inequalities?

Trigonometric inequalities are commonly used in fields such as engineering, physics, and astronomy. They can be used to model and solve problems involving angles, distances, and forces. For example, they can be used to calculate the optimal angle for a ramp or the maximum height of a projectile.

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