Question

Find all the solutions to

2+7csc^2x=12+2csc^2x
.

Assume that n
is any integer.





x=3π/4+2πn and x=7π/4+2πn
x=π/4+(π/2)n and x=5π/4+2πn
x=π/4+(π/2)n
There are no solutions.

Answers

GPT-4o mini
To solve the equation

\[
2 + 7\csc^2 x = 12 + 2\csc^2 x,
\]

we first rearrange the equation by bringing all terms involving \(\csc^2 x\) on one side:

\[
7\csc^2 x - 2\csc^2 x = 12 - 2.
\]

This simplifies to:

\[
5\csc^2 x = 10.
\]

Next, we divide both sides by 5:

\[
\csc^2 x = 2.
\]

Since \(\csc^2 x = \frac{1}{\sin^2 x}\), we can rewrite this as:

\[
\frac{1}{\sin^2 x} = 2,
\]

which implies that:

\[
\sin^2 x = \frac{1}{2}.
\]

Taking the square root of both sides gives:

\[
\sin x = \pm \frac{1}{\sqrt{2}} = \pm \frac{\sqrt{2}}{2}.
\]

The solutions for \(\sin x = \frac{\sqrt{2}}{2}\) occur at:

\[
x = \frac{\pi}{4} + 2\pi n
\]
and
\[
x = \frac{3\pi}{4} + 2\pi n.
\]

The solutions for \(\sin x = -\frac{\sqrt{2}}{2}\) occur at:

\[
x = \frac{5\pi}{4} + 2\pi n
\]
and
\[
x = \frac{7\pi}{4} + 2\pi n.
\]

Combining all of this, the complete set of solutions is:

\[
x = \frac{\pi}{4} + 2\pi n, \quad x = \frac{3\pi}{4} + 2\pi n, \quad x = \frac{5\pi}{4} + 2\pi n, \quad x = \frac{7\pi}{4} + 2\pi n.
\]

Ensuring this matches any of the given options, we can simplify and group them into specific forms. The simplest representation of the solutions is:

\[
x = \frac{\pi}{4} + \frac{\pi}{2} n \quad (n \text{ being even or odd for the other solutions})

\text{ and }
\]
\[
x = \frac{3\pi}{4} + 2\pi n.
\]

The significant options that show combinations of the possible solutions indicate the presence of:

1. \( x = \frac{\pi}{4} + \frac{\pi}{2} n \text{ includes }\)
2. \( x = \frac{5\pi}{4} + 2\pi n \) and similarly for others.

Thus, grouping these solutions, we conclude:

\(\left( x = \frac{\pi}{4} + \frac{\pi}{2} n \text{ and } x = \frac{5\pi}{4} + 2\pi n \text{ are inclusive of the main solutions }\right)\).

Finally, noticing patterns in terms of \( \pi/4 + \frac{\pi}{2} n \):

The option that fits the solutions pattern is:

\[
\boxed{x = \frac{\pi}{4} + \frac{\pi}{2} n}
\]