Question

help with trig equation. Sin(2x)=
a. 2sin(x)
b. 2sin(x)cos(x)
c. cos (x)-sin (x)
2 2
d. sin(2) + sin(x)
e. none of these

Answer 1

I don't want the answer at all I want the process

Answer 2

Using the Sum & Difference Formula (for sine)
\[\sin(u ± v) = \sin(u)\cos(v)± \cos(u)\sin(v)\]

for your expression
\[u=v=x\]

Answer 3

?

Answer 4

sin(2x)=sin(x+x)=

Answer 5

you get\[2\sin x \cos x\]

Answer 6

yes that is correct

Answer 7

ok, and I'm guessing it's not the same for cos, tan, sec, csc, or the inverses

Answer 8

The Sum & Difference Formulas for

Cosine
\[\cos(u ± v) = \cos(u)\cos(v)∓ \sin(u)\sin(v)\]

and Tangent
\[\tan(u±v)=\frac{\tan(u)±\tan(v) }{1∓\tan(u)\tan(v)}\]

Answer 9

b. 2sin(x)cos(x)

Answer 10

Ok, thank you very much, what level trig is this from? I'm trying to refresh myself on everything I took in high school as I am attending university next september but I've been out of school for 5 years so some of it has been completely lost, mostly the trig though, a lot of the calc came back prettyquick and algebra was never really lost

Answer 11

or rather the basic algebra was never lost, some of the more advanced algebra is taking a little bit of time to remember

Answer 12

I don't attempt to remember these formulas
I look them up when i need them

Answer 13

thank you very much :)
btw does
\[(\sqrt{x}+\sqrt{y})^{2}=x+y\]
or
\[(\sqrt{x}+\sqrt{y})^{2}=x+2\sqrt{x}\sqrt{y}+y\]

Answer 14

The second one because\[\Large (a + b)^2 = a^2 + 2ab + b^2\]

Answer 15

ok thought so just wanted to make sure I wasn't forgetting yet another rule. So many I've forgotten and need to remember :/

Answer 16

It will all come back pretty fast though.