My first Proof Tell me what you think please

[Miike012]

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.

 

[Mark44]

I see one mistake. You have sin(90 - theta) = GR/OM. That fraction should be GR/OR, according to your drawing.

 

[Miike012]

Sorry... that's what I ment to say... but besides that... is it ok?

 

[Mark44]

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)

 

[Miike012]

thnks