Question

Verifying trig identities: sec(x+y)=sec x sec y/1-tan x tan y

Answer 1

You can write it as:

\[\sec(x+y) = \frac{1}{\cos(x+y)}\]

And after that use:
\[\cos(x+y) = \cos(x)\cdot \cos(y) - \sin(x) \cdot \sin(y)\]

Answer 2

Can you just try once??

Answer 3

Then can I divide by sin x sin y to get it on the bottom?

Answer 4

You should divide by cos(x)cos(y) as seeing from what our RHS wants,...

Answer 5

Please show me what are you doing? Otherwise we will not be in sync..

Answer 6

It's ok I figured it out(: thanks

Answer 7

If in problem then feel free to tell me..