Question

Determine if (y=tan x + sec x) has any maximums or minimums for -pi/2 < x < pi/2 and justify your answer.

Answer 1

jst take dy/dx

Answer 2

y'=sec(x)^2+sin(x), y'=0 when sec(x)^2=-sin(x), solve, profit!

Answer 3

thanks!!

Answer 4

wait how dou get sin(x)??

Answer 5

Oh, sin(x) was my mistake.

Answer 6

Apparently, I'm still bad at calculus. XP It should be (sin(x))(cos(x)^-2).

Answer 7

i thought derivative of sec x is sec x tan x

Answer 8

yea........

Answer 9

sin(x)/cos(x)^2=tan(x)/cos(x)=tan(x)sec(x)

Answer 10

Same thing. I just didn't remember it, I had to prove it out.

Answer 11

ok so what i do now after i got the derivative ??

Answer 12

sec(x)^2+tan(x)sec(x)=y'=0, tan(x)+1=0, tan(x)=-1, x=arctan(-1)

Answer 13

Woops, my bad. Wait a sec.

Answer 14

(sec(x)+tan(x))=0, tan(x)=-sec(x)

Answer 15

there we go. when do tan(x) and -sec(x) intersect?

Answer 16

wait a minute i need to look at unit circle, i dont have those memorized

Answer 17

sin(x)/cos(x)=-1/cos(x), sin(x)=-1 when is this true?

Answer 18

i think 3pi/4, 7pi/4