Solving sin²x = 1/4 in Quadrants 2, 3, and 4

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In summary, the general process for solving sin²x = 1/4 in Quadrants 2, 3, and 4 is to take the square root of both sides, use the inverse sine function to find the reference angle, and then use the special triangles in each quadrant to determine the possible values of x. It is important to consider these quadrants because the equation has multiple solutions and the sine function in these quadrants has negative values. The special triangles used in each quadrant are a 30-60-90 triangle with a hypotenuse of 2 and a leg of 1 in Quadrant 2, a 45-45-90 triangle with a hypotenuse of √2 and a leg of
  • #1
alpha01
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find all solutions to sin^2 x = 1/4 in pi/2 <= x < 2pi (i.e in quadrants 2,3 and 4)


i understand what i need to do but don't understand sin^2 part. will i need to apply pythagoras therom here first?



thanks
 
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  • #2
[tex]\sin ^2x=(\sin x)^2[/tex]

You can square root both sides, and finding x should be simple then.
 
  • #3
for your question. The notation sin^2 x is another way of writing (sin x)^2, which means the sine of x squared. So when the problem says sin^2 x = 1/4, it is asking you to find all values of x where the sine of x squared is equal to 1/4. This can be solved by taking the square root of both sides, which gives you sin x = 1/2. From there, you can use the unit circle or trigonometric identities to find the solutions in the given range of pi/2 <= x < 2pi. There is no need to use the Pythagorean theorem in this case. I hope this helps clarify the problem for you.
 
1.

What is the general process for solving sin²x = 1/4 in Quadrants 2, 3, and 4?

The general process for solving this equation in these quadrants is to first take the square root of both sides to get sinx = ±1/2. Then, use the inverse sine function to find the reference angle, and finally use the special triangles in each quadrant to determine the possible values of x.

2.

Why is it important to consider Quadrants 2, 3, and 4 when solving sin²x = 1/4?

It is important to consider these quadrants because the equation sin²x = 1/4 has multiple solutions, and the sine function in these quadrants has negative values, which will result in different solutions. It is important to find all possible solutions to accurately solve the equation.

3.

What are the special triangles used in each quadrant to solve sin²x = 1/4?

In Quadrant 2, the special triangle used is a 30-60-90 triangle with a hypotenuse of 2 and a leg of 1. In Quadrant 3, the special triangle used is a 45-45-90 triangle with a hypotenuse of √2 and a leg of 1. In Quadrant 4, the special triangle used is a 30-60-90 triangle with a hypotenuse of 2 and a leg of √3.

4.

What are the possible solutions for sin²x = 1/4 in Quadrants 2, 3, and 4?

The possible solutions for sin²x = 1/4 in these quadrants are x = 150° or 210° in Quadrant 2, x = 135° or 225° in Quadrant 3, and x = 330° or 390° in Quadrant 4. These values can also be written in radians as x = 5π/6 or 7π/6 in Quadrant 2, x = 3π/4 or 5π/4 in Quadrant 3, and x = 11π/6 or 13π/6 in Quadrant 4.

5.

Can the equation sin²x = 1/4 have solutions in Quadrant 1?

No, the equation sin²x = 1/4 does not have solutions in Quadrant 1 because the sine function in this quadrant only has positive values, and the equation requires a negative value for sinx. Therefore, it is not possible to find a solution in Quadrant 1 for this equation.

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