Question

if (cosx)^2 = (1+cos2x)/2

then (secx)^2=2/(1+cos2x)

true?

Answer 1

yeh

Answer 2

this question is telling me to "complete the identity" of (secx)^2-(tanx)^2=?

any thoughts?

Answer 3

i can put them all in terms of cosine and fig it out, yeh?

Answer 4

sec^2x=1+tan^2x

Answer 5

damn you're good

Answer 6

lol :D

Answer 7

so 1+tan^2x-tan^2x =..... 1? LOL

Answer 8

obviously... the tan^2x cancels nd ur left wit 1 so 1=1 thats right....

the answer is (secx)^2-(tanx)^2=1

Answer 9

sorry. did the ... to imply i'm an idiot, pre-obviously :D

Answer 10

u can derive all that from sin^2x+cos^2x=1
if u divide them all by cos^2x u get the equation i wrote