Question

sec(2k90°+theta)=?

Answer 1

@waterineyes @jim_thompson5910 @ajprincess @hartnn

Answer 2

for k=1,3,5,7...
sec(180k+x)=-sec x
for k=2,4,6,8,...
sec(180k+x)=sec x
so overall
sec(180k+x)=((-1)^k)sec x

Answer 3

still have doubts? @bronzegoddess

Answer 4

i don't understand where the -1 came from? is it because for cos the sign changes?

Answer 5

it is because for odd numbers we get negative sign
for even numbers we get positive sign
this effect is represented in maths as (-1)^n
which has same properties
that for odd values of n,its -1
and for even values of n its +1

Answer 6

but 2 is an even number..

Answer 7

yes,it is.....i never implied 2 is odd....

Answer 8

but why is it -1 then, if n=2

Answer 9

no,for n=2,its +1....(-1)^2=1

Answer 10

sorry @hartnn let me reread, maybe i got lost somewhere..

Answer 11

@hartnn why do we have to the power k?

Answer 12

because if k is even answer is +1 * sec x
and if k is odd,answer is -1 * sec x
so k^(-1)

Answer 13

sorry -1^k

Answer 14

oh okay ty