Question

Rewrite with only sin x and cos x.

sin 2x - cos x

Answer 1

Is this just sin x because 2x-x =x?

Answer 2

no - you cannot do that

look up in your text the identity for sin(2x)

you will find an equation which gives you sin 2terms of sinx and cosx

Then substitute that in the above equation and simplify it

Answer 3

no - you cannot do that

look up in your text the identity for sin(2x)

you will find an equation which gives you sin 2x in terms of sinx and cosx

Then substitute that in the above equation and simplify it

Answer 4

sin 2x + 2 sin x cos?

Answer 5

sin 2x = 2 sin x cos x*

Answer 6

yes that is the correct substitution.

So put that in the original and then simplify (by factoring out cos x)

Answer 7

\[2 \sin x \cos x - \cos x = 2 \sin x\]?

Answer 8

@MrNood

Answer 9

no that's not th ecorrect simplification

you should 'factor out' cos x

cosx( ???? )

Answer 10

cos x (2 sin x - 1)

Answer 11

@MrNood

Answer 12

correct

Answer 13

Thank you!