C3 Harmonic identities

MathMeister

10

3sinx +4cos x is 5sin(x+53.1)
They do not graph the same. Why not?
They never seem to graph the same.
Please help +rep

(edited 9 years ago)

Reply 1

Zacken

22

Original post by MathMeister

3sinx +4cos x is 5sin(x+53.1)
They do not graph the same. Why not?
They never seem to graph the same.
Please help +rep

They're graphing the same for me?

To be fair though,

\displaystyle 3 \sin x + 4 \cos x \equiv 5 \sin\bigg(x + \arctan\bigg(\frac{4}{3}\bigg) \bigg)

.

MSP4411f48ic095h4869d800003dg81014g8b878eh.gif6.0KB

Reply 2

MathMeister

OP

10

Original post by Zacken

They're graphing the same for me?

What programme are you using if you don't mind me asking?
I have geogebra and have tried Wolfram alpha and they do not graph the same :/ :redface:

Reply 3

Zacken

22

Original post by MathMeister

What programme are you using if you don't mind me asking?
I have geogebra and have tried Wolfram alpha and they do not graph the same :/ :redface:

Wolfram Alpha itself, make sure that you're using exclusively degrees or radians because of that 53.1 component of your sine function. Convert it to radians then input it back into Wolfram Alpha and see? :smile:

Reply 4

Zacken

22

Update: They graph the same in Mathematica as well, if I use it in Radians mode.

Reply 5

MathMeister

OP

10

Original post by Zacken

Wolfram Alpha itself, make sure that you're using exclusively degrees or radians because of that 53.1 component of your sine function. Convert it to radians then input it back into Wolfram Alpha and see? :smile: