My first Proof Tell me what you think please

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Homework Help Overview

The discussion revolves around a proof involving trigonometric identities, specifically the relationship sin(90-theta) = cos(theta), along with related functions such as tan, cot, sec, and csc. The original poster seeks feedback on the correctness of their proof.

Discussion Character

  • Exploratory, Conceptual clarification

Approaches and Questions Raised

  • The original poster presents a proof and asks for validation. Participants point out a mistake in the proof related to a geometric representation and inquire about the overall correctness after the error is acknowledged.

Discussion Status

The discussion is ongoing, with participants providing feedback on specific aspects of the proof. One participant suggests a method to demonstrate congruence between triangles to strengthen the proof, indicating a productive direction without reaching a final consensus.

Contextual Notes

There is an indication that the instructor may have high standards for the proof's presentation, which could affect how the original poster approaches corrections and justifications.

Miike012
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Proving... sin(90-theta) = cos(theta)
along with tan.. cot.. and sec.. csc...
short proof... please let me know if it is correct... thank you.
 

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I see one mistake. You have sin(90 - theta) = GR/OM. That fraction should be GR/OR, according to your drawing.
 
Sorry... that's what I ment to say... but besides that... is it ok?
 
Yeah. Fix that and you should be good.

In case your instructor is very picky, you can show that OS = GR by showing that the triangles OSR and OGR are congruent. Both are right triangles, and angle SOR = angle GRO. Also, angle GOR = angle ORS. Since two angles and the included side of one triangle are congruent to the corresponding two angles and included side of the other triangle, the two triangles are congruent. (ASA - short for angle-side-angle)
 
thnks
 

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