Question

Is there any easy way to figure out what the first step should be with Trig simplifying/proofs?

Could I get a hint for the first step in

cos(x)+sin(x)
-----------
cos(2x)

Answer 1

expand the bottom

Answer 2

whenever u see double angles expand to become single angles

Answer 3

So expand to
\[\cos x + \sin x \div \cos^2x -\sin^2x\] ?

Answer 4

The next step I did from that is take the reciprocal:

cos^2(x) - sin^2(x)
- ---------------
cos(x) +sin(x)

I intended to just divide out the exponent, but I'm 90% sure that's impossible because of the presence of the addition/subtraction.

Answer 5

no, for starters that would get you going round in circles

Answer 6

this one is kinda of easy and a little tricky

Answer 7

you are pretty much finsihed with what you did before

Answer 8

\[\frac{\cos(x) +\sin(x)}{\cos^2(x)-\sin^2(x)} \]

Answer 9

follow from that

Answer 10

So with that one, it's just the one step?

Answer 11

no, thats not finished yet lol

Answer 12

what if I said simplify \[\frac{u+3}{u^2 -9} \]

Answer 13

if a very similar question

Answer 14

(I'm retaking this math course, and this is exactly what I was struggling with the first time, I think I just don't know basic algebra which is why I can't do these very well D:)

I'm not sure how to divide things out when there's additions and the numbers/variables don't have common multiples...

Answer 15

its just an idenity that you must remember

that (a^2 -b^2) = (a-b)(a+b)

Answer 16

its not that hard to remember

Answer 17

always looking for sqaure of numbers

Answer 18

why you should know atleast up to your 12 times tables off you head