Help!

[Nukedsodapop 5,000+ posts]

Ok, im sitting here doing my Hw (amazing actually) and Im supposed to graph this...

x= 2 + 5cos(Pie/10)(x-3)

Which is supposed to be a sine wave function

But instead i get a straght line going from SW to NE, any help?

the calculator is a TI-83 Plus

Click to read more...

 

[sumone 10+ year member]

zoom out....

 

[sumone 10+ year member]

Matterfact I take that back...that's not a sine wave function...

5cos(Pie/10) is a constant...

 

[sumone 10+ year member]

y = 2 + 5cos(Pie/10)(x-3)

y = 2 + 5cos(pi/10)x - 3*5cos(pi/10)

y = 5cos(pi/10)x - 15cos(pi/10) + 2

5cos(pi/10) = m and

-15cos(pi/10) + 2 = b

= linear

 

[Nukedsodapop 5,000+ posts]

but thats the equation of the graph...

Amplitude = 5

Period = Pie/10

Sinusoidal Axis = 2

Phase Displacement = 3

x = C + Acos(B)(x-D)

Whats up?

 

[Nukedsodapop 5,000+ posts]

anyone? help needed quick

 

[Nukedsodapop 5,000+ posts]

???

 

[j3bus2k3 5,000+ posts]

make sure your calculator is in radian mode is the only thing i can think of....

 

[MastaFlex 10+ year member]

man took calc last year i wish i remembered some of it

 

[ToyTundra 10+ year member]

first off that's not calc, just trig.

I agree you may be in degree mode, so switch to radians

It was probably entered wrong. Go crazy with the parethesis

y= 2 + 5cos[(Pie/10)(x-3)] and/or multiply out the insides of the cos function before entering it into your calculator

 

[Nukedsodapop 5,000+ posts]

thats what was wrong with it, i didnt have the two other parentheses

thanks man

 

[Nukedsodapop 5,000+ posts]

Alright, here's a new one...

turn this expression

csc x tan x

to this one

sec x

...

Go.

lol

 

[sumone 10+ year member]

turn this expression
csc x tan x

to this one

sec x

Man that's too easy. I'm not gonna give you the answer....just think though:

csc x = 1/(sin x)

tan x = (sin x)/(cos x)

all you gotta do is simplify [1/(sinx)] * [(sin x)/(cos x)] (think...what gets canceled out...) ....sin x

so you're left with 1/(cos x) = sec x



...and I said I wasn't gonna give you the answer! But really dude, what was causing you some difficulty?

 

[Nukedsodapop 5,000+ posts]

that whole thing, those screw me up