Solving a Basic Trigonometry Doubt: Where to Learn?

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    Doubt Trigonometry
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Discussion Overview

The discussion revolves around a basic trigonometry question regarding the transformation of the expression 3cos(2t) + 4sin(2t) into the form 5cos(2t - 53.13°). Participants also share resources for learning basic trigonometry.

Discussion Character

  • Exploratory, Technical explanation, Homework-related

Main Points Raised

  • One participant expresses a doubt about the transformation of a trigonometric expression and seeks resources for learning.
  • Another participant provides a detailed explanation using the cosine addition formula and suggests a method to rewrite the expression, including defining a relationship between sine and cosine.
  • A third participant shares a link to a website that may help with learning basic trigonometry.
  • A later reply thanks the responder for both the explanation and the resource link.

Areas of Agreement / Disagreement

Participants do not express disagreement; however, the initial question remains open-ended as it seeks further learning resources.

Contextual Notes

The discussion does not address any limitations or assumptions explicitly, but the transformation relies on the cosine addition formula and specific angle definitions.

Who May Find This Useful

Individuals seeking help with basic trigonometry concepts or looking for resources to learn trigonometry may find this discussion useful.

skan
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I have basic trignometry doubt

how to u get 5cos(2t-53.13degrees) from 3cos2t + 4 sin2t.

Can someone suggest a site from where I can lean basic trinometry

thanks.
skan
 
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well, nice question...
use cos(x-y)=cos(x)cos(y) + sin(x)sin(y).

3cos2t + 4sin2t = 3(cos2t + (4/3)sin2t). The trick is to define 4/3 = tan(y)=siny/cosy where y = 53,13°. Now you have 3(cos2t + (siny/cosy)sin2t). or this becomes following expression : (3/cosy)(cosy * cos2t + siny * sin2t) =
(3/cosy)cos(2t - 53.13°) and cosy = cos(53.13°) = 0.6

3/cosy = 3/0.6 = 5

problem solved

regards
marlon
 
Check out this site...


http://www.ping.be/~ping1339/index.html#Main-Purpose-=-MATH-

marlon
 
Last edited by a moderator:
Thanks a lot for the answer and the great link!
 

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