Doubt about trigonometry Identities from sin α

Click For Summary
SUMMARY

The discussion focuses on calculating trigonometric identities for a right triangle given the sine value sin α = √3/2. The user, Ray, seeks guidance on deriving the other trigonometric functions without initial values for the hypotenuse or legs of the triangle. The community suggests utilizing the unit circle, where sin(θ) corresponds to the y-coordinate and cos(θ) to the x-coordinate, emphasizing the Pythagorean theorem x² + y² = 1 to find the necessary values. The approach confirms that the sine function is positive in two quadrants, leading to two possible angles for α.

PREREQUISITES
  • Understanding of basic trigonometric functions (sine, cosine, tangent)
  • Familiarity with the unit circle and its properties
  • Knowledge of the Pythagorean theorem
  • Ability to manipulate trigonometric identities
NEXT STEPS
  • Study the unit circle and its application in trigonometry
  • Learn how to derive trigonometric identities from sine and cosine values
  • Explore the concept of reference angles and their significance in trigonometry
  • Practice solving trigonometric equations involving sine and cosine
USEFUL FOR

Students learning trigonometry, educators teaching trigonometric identities, and anyone needing to solve problems involving right triangles and trigonometric functions.

Ray9927
Messages
1
Reaction score
0
Thread moved from the technical forums, so no Homework Help Template is shown
Hi all! I'm Ray and I'm new to this community, it's a pleasure!

I'm trying to resolve a trigonometry exercise where I have to calculate the trigonometry Identities of a right triangle but in the specifications they don't show me any common data (hypotenuse or cathethus values), they just leave me a sen α= √3/ 2

I know how to calculate the identities parting from the main two values, maybe the hypotenuse and one of the cathethus, then using the The Pythagorean Theorem to isolate the remaining variable, and finally reflecting the values in the identities formules (sen, cos, tan...) to finish the exercise but, this is completely new for me...

What should I do to proceed with this type of exercise? should I use the sen formule: Opposite/ hypotenuse with √3/ 2 to obtain the first values? i mean √3= Opposite and 2= hypotenuse?
 
Physics news on Phys.org
Ray9927 said:
Hi all! I'm Ray and I'm new to this community, it's a pleasure!

I'm trying to resolve a trigonometry exercise where I have to calculate the trigonometry Identities of a right triangle but in the specifications they don't show me any common data (hypotenuse or cathethus values), they just leave me a sen α= √3/ 2

I know how to calculate the identities parting from the main two values, maybe the hypotenuse and one of the cathethus, then using the The Pythagorean Theorem to isolate the remaining variable, and finally reflecting the values in the identities formules (sen, cos, tan...) to finish the exercise but, this is completely new for me...

What should I do to proceed with this type of exercise? should I use the sen formule: Opposite/ hypotenuse with √3/ 2 to obtain the first values? i mean √3= Opposite and 2= hypotenuse?
Trig functions are usually developed for the unit circle:


http://www.regentsprep.org/regents/math/algtrig/att5/unitcircle.gif

The sine and cosine functions have maximum amplitude of 1, so the unit circle works fine for these types of calculations.

In the circle above, sin (θ) = y and cos (θ) = x and the Pythagorean relation is x2 + y2 = 1
 
Ray9927 said:
Hi all! I'm Ray and I'm new to this community, it's a pleasure!

I'm trying to resolve a trigonometry exercise where I have to calculate the trigonometry Identities of a right triangle but in the specifications they don't show me any common data (hypotenuse or cathethus values), they just leave me a sen α= √3/ 2

I know how to calculate the identities parting from the main two values, maybe the hypotenuse and one of the cathethus, then using the The Pythagorean Theorem to isolate the remaining variable, and finally reflecting the values in the identities formules (sen, cos, tan...) to finish the exercise but, this is completely new for me...

What should I do to proceed with this type of exercise? should I use the sen formule: Opposite/ hypotenuse with √3/ 2 to obtain the first values? i mean √3= Opposite and 2= hypotenuse?

Well, yes. But I would think about the unit circle and realize there are two quadrants where the sine function is positive. So you get two different angles and then you can add ##\pm 2\pi## to each.

[Edit] I see SteamKing posted while I was still editing...
 

Similar threads

  • · Replies 18 ·
Replies
18
Views
2K
Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
3
Views
5K
Replies
8
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
Replies
2
Views
2K