Question

can some1 help? if so thank you
state whether or not the equation is identity if so prove it
sec(-x)=sec(x)
sec^2(x)-csc^2(x) = tan^2(x) - cot^2(x)
cos^2(sec(x)+1)^2=(1+cosx)^2

Answer 1

yes they are three different problems any help wld be apreciated i dont understand this stuff
thanks

Answer 2

cos(x) = cos(-x) so 1st is true

Answer 3

since cosx is an even function! :)

Answer 4

that means it is symmetric about the y-axis!

Answer 5

what can say about 1/cos(-x)=1/cosx now?

Answer 6

i will be back i must eat :)