Math Problem Statement

Select one or more expressions that together represent all solutions to the equation. Your answer should be in radians. Assume [n] is any integer.

[9\sin(18x)+11=2]

Choose all answers that apply:

Choose all answers that apply:

(Choice A)   

[-\dfrac{\pi}{2}+n\cdot2\pi]

A

[-\dfrac{\pi}{2}+n\cdot2\pi]

(Choice B)   

[-\dfrac{\pi}{36}+n\cdot\dfrac{\pi}{9}]

B

[-\dfrac{\pi}{36}+n\cdot\dfrac{\pi}{9}]

(Choice C)   

[n\cdot\pi]

C

[n\cdot\pi]

(Choice D)   

[\dfrac{\pi}{36}+n\cdot\dfrac{\pi}{9}]

D

[\dfrac{\pi}{36}+n\cdot\dfrac{\pi}{9}]

(Choice E)   

[\dfrac{\pi}{2}+n\cdot\dfrac{\pi}{11}]

E

[\dfrac{\pi}{2}+n\cdot\dfrac{\pi}{11}]

(Choice F)   

[\dfrac{\pi}{2}+n\cdot\pi]

F

[\dfrac{\pi}{2}+n\cdot\pi]

Solution

Let's solve the given equation step by step:

9sin(18x)+11=29\sin(18x) + 11 = 2

First, isolate the sine term:

9sin(18x)=2119\sin(18x) = 2 - 11 9sin(18x)=99\sin(18x) = -9

Now, divide both sides by 9:

sin(18x)=1\sin(18x) = -1

The general solution for sin(θ)=1\sin(\theta) = -1 is:

θ=3π2+2nπwhere n is any integer\theta = \dfrac{3\pi}{2} + 2n\pi \quad \text{where } n \text{ is any integer}

Substitute θ=18x\theta = 18x:

18x=3π2+2nπ18x = \dfrac{3\pi}{2} + 2n\pi

Now, solve for xx:

x=3π36+nπ9x = \dfrac{3\pi}{36} + n\cdot\dfrac{\pi}{9}

Simplify the fraction:

x=π12+nπ9x = \dfrac{\pi}{12} + n\cdot\dfrac{\pi}{9}

This is one possible solution. However, let's consider the additional periodic solutions.

The sine function sin(18x)\sin(18x) has a period of 2π18=π9\dfrac{2\pi}{18} = \dfrac{\pi}{9}, so other solutions within the period might exist.

Considering the periodicity and the general solution, the correct forms must match the equivalent angles where sin(18x)=1\sin(18x) = -1 at 3π2\dfrac{3\pi}{2} and its periodic multiples.

So let's check the options:

  • Choice A: π2+n2π-\dfrac{\pi}{2} + n\cdot 2\pi does not match our derived solution.
  • Choice B: π36+nπ9-\dfrac{\pi}{36} + n\cdot\dfrac{\pi}{9} does not match the correct angles either.
  • Choice C: nπn\cdot\pi is not correct, as the sine function only equals 1-1 at specific angles, not all multiples of π\pi.
  • Choice D: π36+nπ9\dfrac{\pi}{36} + n\cdot\dfrac{\pi}{9} does not match.
  • Choice E: π2+nπ11\dfrac{\pi}{2} + n\cdot\dfrac{\pi}{11} is incorrect because π11\dfrac{\pi}{11} is unrelated to the actual period of the function.
  • Choice F: π2+nπ\dfrac{\pi}{2} + n\cdot\pi is unrelated to the solution derived.

None of the options provided accurately represent the solution derived from sin(18x)=1\sin(18x) = -1, which is:

x=π12+nπ9x = \dfrac{\pi}{12} + n\cdot\dfrac{\pi}{9}

Therefore, none of the answer choices correspond to the correct solution set.

Would you like further clarification on any part of the solution?

Here are some related questions:

  1. What would be the general solution for sin(kx)=1\sin(kx) = 1?
  2. How does the periodicity of the sine function affect the number of solutions within a given interval?
  3. How can we use the unit circle to determine the exact angles where sin(x)=1\sin(x) = -1?
  4. What if the equation involved cos(18x)=1\cos(18x) = -1 instead of sine—how would the solutions change?
  5. How do different coefficients of xx inside a sine function influence the solution set?

Tip: Always double-check the periodicity of the trigonometric function when solving equations to ensure all possible solutions are considered.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Periodicity of Trigonometric Functions
Solving Trigonometric Equations

Formulas

General solution for sin(theta) = -1

Theorems

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Suitable Grade Level

Advanced High School