Question

engineering cal 2 - solve for x ---- arccos x = arcsec x

Answer 1

I understand that y=arccos x and y=arcsec x but they are giving me the answer x =+/- 1

Answer 2

um, arcsec(x) = arccos(1/x) --> x = 1/x --> x^2 = 1 --> x = +-1

Answer 3

sec x = cos x ---> 1/cos x = cos x ---> 1 = cos x ^2 ----> +- 1 = cos x ??

Answer 4

is this new problem?

Answer 5

no no no I'm trying to make sense of your post. where did you get arccos (1/x)?

Answer 6

but you are correct above....best way to see it is use unit circle,


say x = cos(theta) --> theta = arccos(x) then sec(theta) = 1/x --> theta = arcsec(1/x)

Answer 7

yes sir. thank you very much

Answer 8

no problem