Trig. Equations (1 Viewer)

[Smile12345]

Hello All.

Could someone please help with the following question?

Solve

Thanks for your help in advance.

 

[Drongoski]

Then cos x = 1 or -1

 

[Smile12345]

Answers say x = 0, 180, 360 degrees...

 

[Smile12345]

Then cos x = 1 or -1

Yeah ok, thanks... Maybe you are going further than I need?

 

[Drongoski]

Answers say x = 0, 180, 360 degrees...

If question specifies the range, then positive angles. 0, 180, 360 deg same as 0, pi, 2 pi etc

 

[RealiseNothing]

If question specifies the range, then positive angles. 0, 180, 360 deg same as 0, pi, 2 pi etc

I have a feeling Smile hasn't learnt radians yet.

 

[Smile12345]

I have a feeling Smile hasn't learnt radians yet.

You're right!! I need the extra extra basics!

 

[Drongoski]

I have a feeling Smile hasn't learnt radians yet.

Ah thanks; never thought of that.

 

[Smile12345]

Ah thanks; never thought of that.

Are you able to help me any further then?? Thanks.

Sorry I should have put the range in 0 deg less than or = to, theta, less than or equal to 360 deg.

 

[Drongoski]

Just post your questions. There are so many very helpful and abler helpers ready to lend you a hand, as you are no doubt aware.

 

[Smile12345]

Just post your questions. There are so many very helpful and abler helpers ready to lend you a hand, as you are no doubt aware.

Yes, I certainly do... I really appreciate their help...

So how do you do the original post without learning about radians?

Thanks.

 

[enigma_1]

Yes, I certainly do... I really appreciate their help...

So how do you do the original post without learning about radians?

Thanks.

Basically the radian thing is easy, as I know it.
The pi symbol denotes 180 degrees.

If you want to convert something in terms of pi, eg 30 degrees, then you do 30 / 180 = 1 / 6 and then you times it by pi,
so it is pi / 6.

Eg convert 60 to radian.

That would be 60 / 180 = 1 / 3 = pi / 3

Drongoski has given you the General solutions for the question which looks at all the possible values without a domain restriction for the x values.

-----

So you know how cos^x = 1
:. cos x = +1 or -1

Solve for x.

:. x = 0, 180, 360 + 0, 360 + 180 .... (Using the ASTC Rule)

Since we know radian (where pi = 180 degrees), this can be re-written as:

:. x = 0, pi, +/- 2 pi, +/- 3 pi ....

 

[Smile12345]

Basically the radian thing is easy, as I know it.
The pi symbol denotes 180 degrees.

If you want to convert something to pi, eg 30 degrees, then you do 30 / 180 = 1 / 6 and then you times it by pi,
so it is pi / 6.

Eg convert 60 to radian.

That would be 60 / 180 = 1 / 3 = pi / 3

Drongoski has given you the General solutions for the question which looks at all the possible values without a domain restriction.

Yeah, ok then... No, it's not that hard... I think you can do it without this - I don't this is in the Mathematics course (yet)?!....

Yeah, Drongoski has been very helpful. Thanks.

 

[Smile12345]

-----

So you know how cos^x = 1
:. cos x = +1 or -1

Solve for x.

:. x = 0, 180, 360 + 0, 360 + 180 .... (Using the ASTC Rule)

Since we know radian (where pi = 180 degrees), this can be re-written as:

:. x = 0, pi, +/- 2 pi, +/- 3 pi ....

Yeah ok, thanks heaps for you edited comments... Much appreciated.

 

[levaly]

Here is a step by step solution:

http://www.symbolab.com/solutions/trigonometric_equations?query=cos^{2}x=1