Question

can someone show me how to get from
y=sec^2x-tan^2x to y=(tan^2x+1)-tan^2x ?

Answer 1

\[y=\sec ^{2}x-\tan ^{2}x\] to \[y=(\tan^{2}x+1)-\tan^{2}x\]

Answer 2

sec^2x = 1+ tan^2x is a standard identity

Answer 3

oh duh... sigh.

Answer 4

you need to remember it

Answer 5

thanks, writing it down now :) - again

Answer 6

other 2 are :
cosec^2x = 1+cot^2x
sin^2x+cos^2x = 1

Answer 7

cosec is csc?

Answer 8

yes

Answer 9

wow these identities save LOTS of time

Answer 10

and solve lots of problems :)

Answer 11

again, thanks