Question

cos(-x)=-cosx for all values of x.
true or false?

Answer 1

true !

Answer 2

sin(-x)=-sin(x)
csc(-x)=-csc(x)

cos(-x)=cos(x)
sec(-x)=sec(x)

tan(-x)=-tan(x)
cot(-x)=-cot(x)


all of these rule !

Answer 3

thank you. one more question...

Answer 4

sure, shoot and I'll try to help !

Answer 5

\[\cos a/2 =\pm \sqrt{1-\cos a/2}\]

Answer 6

is that one true or false?

Answer 7

for all values of a. sorry i forgot to mention that

Answer 8

http://www.purplemath.com/modules/idents.htm

look at the half angle identities. I am pretty sure - FALSE !

Answer 9

Do you want to know how to find cos(340) sin(75) and all of those things?

I was just now reviewing them from last year.

Answer 10

no its fine. they are just true or false questions and that website helped me a lot. so thank you so much!

Answer 11

Anytime !