Question

Rewrite with only sin x and cos x.

sin 3x

Answer 1

sin (3x) like this ?

Answer 2

yes i have to rewrite it with only sin(x) and cos(x)

Answer 3

\[\large\rm \sin(\color{red}{3x}) = \sin(\color{red}{2x+x})\]

Answer 4

Simplify the numerator with the sine expression by taking A = B = x and simplify the denominator using A = x and B = 2x. The resulting denominator will have sin(2x) and cos(2x) which you can write in terms of sin(x) and cos(x) using the expressions above. Finally if you use the fact that sin2(x) + cos2(x) = 1 you can write sin(2x)/sin(3x) as a function of cos(x) alone.

Answer 5

you can separate 3x as 2x+x now use the identity \[\large\rm \sin(a+b)= \sin a * \cos b + \cos a *\sin b\]

Answer 6

sin(x+2x)=sinxcos2x+sinsxcosx

Answer 7

hmm first term is correct and 2nd one u forgot something there :=))

Answer 8

Yeah

Answer 9

oh yeah sorry i meant to put a 2 after sin

Answer 10

yes right
\[\large\rm \sin(x+2x)= \sin (x)*\cos(2x) + \cos (x) *\sin(2x)\]

Answer 11

what is the next step?

Answer 12

ummm

Answer 13

hmm wait a sec plz let me do it first :3p-_;

Answer 14

alright now we have to use Double angle formula
\[\rm \sin(2a)= 2 \sin(a)\cos(a)\]\[\large\rm \cos(2a)= 2\cos^2(a)-1\]

Answer 15

hey

Answer 16

\[\large\rm \sin (x)* \color{Red}{\cos(2x)} + \cos (x) * \color{green}{\sin(2x)}\]

Answer 17

stop making new accounts -.-

Answer 18

\[\rm \sin(2a)=\color{green}{ 2 \sin(a)\cos(a)}\]\[\large\rm \cos(2a)=\color{red}{ 2\cos^2(a)-1}\]
substitute cos(2x) and sin(2x) for these identities
\[\large\rm \sin (x)* \color{Red}{2cos(x)^2-1} + \cos (x) * \color{green}{2sin(x)cos(x)}\]
now simplify

Answer 19

I think i know this

Answer 20

?

Answer 21

stop spamming
i know AlabamaCrimsonTide , FloridaGators and BoiseStateBroncos all of them r ur accounts!! :=))

Answer 22

Who?

Answer 23

Ummm Football teams

Answer 24

Not me

Answer 25

Yes you

Answer 26

NO!!!!!

Answer 27

YES!!!!!!!!