Question

Find all of the Radian solutions:

sec 3x - sqrt2 = 0

stuck and I don't know what to do!

Answer 1

You know that sec(x) = 1/cos x. Add sqrt2 to both sides, multiply by cos x / sqrt2. Now you've got cos x = 1 / sqrt2:

Answer 2

oops i didn't see that you said 3x. follow my argument again but replace x by 3x. you have cos 3x = 1 / sqrt2. Find all solutions in 3x and divide by 3.

Answer 3

so, it would be pi/4 and 7pi/4, but if you divide by 3, it would be pi/12 and 7pi/12, right?

Answer 4

yes, plus any multiple of 2pi/3