Explaining the Solution for secx=4 in Calculator Format (Ti-89) for Range 0-2pi

[HANNONKEVINP]

Homework Statement

I was supposed to use my calculator to get the answer of secx=4 for the range 0 to 2pi. I use the Ti-89.

Homework Equations

calculator format solve (secx=4,x)

The Attempt at a Solution

I get an answer, but it has a weird notation at the end of 2pi.

2pi(weird notation)1 +/- arccos (1/4) In radians, obviously

The notation looks like a lower case e, but instead, it breaks about halfway under the top loop. Sorry, for my vague info. I can't take a picture of it because i don't half no camera

 

[Jonathan G]

The TI-89 has the weird symbol to let you know their are more than 1 solution. Take f(x)=cos(x) for example. If you input it into the 89 for where f(x) = 0 you should right away know that f(x) will cross 0 in more than 1 place. The 89 will give you something like (pi/2)(weird symbol). But you know right away from the graph (if you know what it looks like) that it does not only cross at pi/2 but at every half wavelength starting at pi/2 (if your talking of only the positive side).

 

[HANNONKEVINP]

The TI-89 has the weird symbol to let you know their are more than 1 solution. Take f(x)=cos(x) for example. If you input it into the 89 for where f(x) = 0 you should right away know that f(x) will cross 0 in more than 1 place. The 89 will give you something like (pi/2)(weird symbol). But you know right away from the graph (if you know what it looks like) that it does not only cross at pi/2 but at every half wavelength starting at pi/2 (if your talking of only the positive side).

Alright, thank you.