# Trigonometric Functions help

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Hi

I'm trying to learn trigonometric functions,

The question is to:

express 4.sin(Ωt+1.2°) in the form of a.sin(Ωt) ± b.cos(Ωt)

I wanna use an argand diagram to verify my answer

Thanks!

I'm trying to learn trigonometric functions,

The question is to:

express 4.sin(Ωt+1.2°) in the form of a.sin(Ωt) ± b.cos(Ωt)

I wanna use an argand diagram to verify my answer

Thanks!

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(Original post by

What is the question?

**poorform**)What is the question?

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(Original post by

express 4.sin(Ωt+1.2°) in the form of a.sin(Ωt) ± b.cos(Ωt)

**dc2209**)express 4.sin(Ωt+1.2°) in the form of a.sin(Ωt) ± b.cos(Ωt)

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(Original post by

Are you familiar with the addition formulae for trigonometric functions?

**razzor**)Are you familiar with the addition formulae for trigonometric functions?

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#7

These might help you out:

sin(A+B) = sin(A)cos(B) + sin(B)cos(A)

sin(A-B) = sin(A)cos(B) - sin(B)cos(A)

cos(A+B) = cos(A)cos(B) - sin(A)sin(B)

cos(A-B) = cos(A)cos(B) + sin(A)sin(B)

sin(A+B) = sin(A)cos(B) + sin(B)cos(A)

sin(A-B) = sin(A)cos(B) - sin(B)cos(A)

cos(A+B) = cos(A)cos(B) - sin(A)sin(B)

cos(A-B) = cos(A)cos(B) + sin(A)sin(B)

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(Original post by

These might help you out:

sin(A+B) = sin(A)cos(B) + sin(B)cos(A)

sin(A-B) = sin(A)cos(B) - sin(B)cos(A)

cos(A+B) = cos(A)cos(B) - sin(A)sin(B)

cos(A-B) = cos(A)cos(B) + sin(A)sin(B)

**razzor**)These might help you out:

sin(A+B) = sin(A)cos(B) + sin(B)cos(A)

sin(A-B) = sin(A)cos(B) - sin(B)cos(A)

cos(A+B) = cos(A)cos(B) - sin(A)sin(B)

cos(A-B) = cos(A)cos(B) + sin(A)sin(B)

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#9

So substitute the appropriate values into the formula for sin(A+B) and see what you get. Compare it with a.sin(Ωt) ± b.cos(Ωt).

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(Original post by

So substitute the appropriate values into the formula for sin(A+B) and see what you get. Compare it with a.sin(Ωt) ± b.cos(Ωt).

**razzor**)So substitute the appropriate values into the formula for sin(A+B) and see what you get. Compare it with a.sin(Ωt) ± b.cos(Ωt).

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#11

(Original post by

Ok so 4[sin+Ωt] x cos1.2 + cosΩt x sin 1.2]

**dc2209**)Ok so 4[sin+Ωt] x cos1.2 + cosΩt x sin 1.2]

Also, I don't why you put another squared bracket after the Ωt. The 4 needs to multiply the whole thing.

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#12

[QUOTE=dc2209;57214085]Hi

I'm trying to learn trigonometric functions,

The question is to:

express 4.sin(Ωt+1.2°) in the form of a.sin(Ωt) ± b.cos(Ωt)

Hello. I have attahced a solution below. If you obtain a copy of the Edexcel A Level Mathematics core 3 syllabus, it explains how to undertake Trig questions like yours, using compound angle formulae. It is a compound angle as A is not the same as B. If A was the same as B, then it would be Double Angle Formulae.

As for an Argand Diagram, these are used in conjunction with Complex Numbers, which are part of the Edexcel Further Pure 1 syllabus.

For further help and support on Trig Identities, please visit Exam Solutions.net or www.m4ths.com.

Thanks

Vandomo

I'm trying to learn trigonometric functions,

The question is to:

express 4.sin(Ωt+1.2°) in the form of a.sin(Ωt) ± b.cos(Ωt)

Hello. I have attahced a solution below. If you obtain a copy of the Edexcel A Level Mathematics core 3 syllabus, it explains how to undertake Trig questions like yours, using compound angle formulae. It is a compound angle as A is not the same as B. If A was the same as B, then it would be Double Angle Formulae.

As for an Argand Diagram, these are used in conjunction with Complex Numbers, which are part of the Edexcel Further Pure 1 syllabus.

For further help and support on Trig Identities, please visit Exam Solutions.net or www.m4ths.com.

Thanks

Vandomo

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[QUOTE=van.domo;57379937]

Ah thanks, that makes sense.

in my notes I have d = tan^(-1) 0.083/3.996 = (this should be 2 degrees), is this for construction of the argand diagram?

(Original post by

Hi

I'm trying to learn trigonometric functions,

The question is to:

express 4.sin(Ωt+1.2°) in the form of a.sin(Ωt) ± b.cos(Ωt)

Hello. I have attahced a solution below. If you obtain a copy of the Edexcel A Level Mathematics core 3 syllabus, it explains how to undertake Trig questions like yours, using compound angle formulae. It is a compound angle as A is not the same as B. If A was the same as B, then it would be Double Angle Formulae.

As for an Argand Diagram, these are used in conjunction with Complex Numbers, which are part of the Edexcel Further Pure 1 syllabus.

For further help and support on Trig Identities, please visit Exam Solutions.net or www.m4ths.com.

Thanks

Vandomo

**dc2209**)Hi

I'm trying to learn trigonometric functions,

The question is to:

express 4.sin(Ωt+1.2°) in the form of a.sin(Ωt) ± b.cos(Ωt)

Hello. I have attahced a solution below. If you obtain a copy of the Edexcel A Level Mathematics core 3 syllabus, it explains how to undertake Trig questions like yours, using compound angle formulae. It is a compound angle as A is not the same as B. If A was the same as B, then it would be Double Angle Formulae.

As for an Argand Diagram, these are used in conjunction with Complex Numbers, which are part of the Edexcel Further Pure 1 syllabus.

For further help and support on Trig Identities, please visit Exam Solutions.net or www.m4ths.com.

Thanks

Vandomo

Ah thanks, that makes sense.

in my notes I have d = tan^(-1) 0.083/3.996 = (this should be 2 degrees), is this for construction of the argand diagram?

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