Given sinx=4/5, cosy = 7/25. Find the following

  • Thread starter Thread starter Random-Hero-
  • Start date Start date
Click For Summary

Homework Help Overview

The problem involves finding trigonometric values for angles x and y in the first quadrant, given sin(x) = 4/5 and cos(y) = 7/25. The specific tasks include determining cos(x), sin(y), and sin(x+y).

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss using the identity sin²(x) + cos²(x) = 1 to find cos(x). There is uncertainty about how to proceed with the calculations for sin(y) and sin(x+y), with some participants expressing confusion about the formulas needed.

Discussion Status

Some participants have made progress on parts a) and b), while others are exploring how to approach part c). Guidance has been offered regarding relevant trigonometric identities, and there is an ongoing exchange of ideas without a clear consensus on the final steps.

Contextual Notes

Participants are working within the constraints of the problem statement and are navigating the complexities of trigonometric identities without complete information on the relationships between the angles.

Random-Hero-
Messages
40
Reaction score
0

Homework Statement



Angles x and y are located in the first quadrant such that sinx=4/5, and cosy = 7/25.

a) Determine an exact value of cosx.

b) Determine an exact value of siny.

c) Determine an exact value for sin(x+y)


Homework Equations



Compound angle formulas perhaps? I don't really know, that's the problem!

The Attempt at a Solution



I'm really at a loss here, do I just sub those into some formula or something? Can anyone help me out? Or get me pointed in the right direction? thanks in advance!
 
Physics news on Phys.org
Let's start with part a). Have you thought about [tex]sin^2(x) + cos^2(x) = 1[/tex]?
 
Holy smoke I can't believe I missed that! thanks hitman! I owe you one!

Now for the last 2 lil buggers!
 
well I got a and b, now how would I do c? :|
 
Nevermind, I got it, thanks for your help hitman! I don't know how on Earth i missed that!
 
sin(x+y) = sinx*cosy+siny*cosx
 

Similar threads

Trigonometry: count sin+cos when tg-ctg=-7/12
  • · Replies 7 ·
Replies
7
Views
3K
Tangent line approximation with sinx/x + siny/y = C
  • · Replies 5 ·
Replies
5
Views
9K
Finding integrals of the product of trig functions
  • · Replies 3 ·
Replies
3
Views
2K
Solving Integral of sqrt(sinx)/(sqrt(sinx)+sqrt(cosx))dx: Help Needed
  • · Replies 9 ·
Replies
9
Views
2K
Integration problem ∫1/(√3 sinx+ cosx) dx
  • · Replies 8 ·
Replies
8
Views
2K
Evaluating Trigonometric Integral
  • · Replies 5 ·
Replies
5
Views
2K
Solving x+3y=4-kz & 4x-2y=5+10z: Find the Solution Here
  • · Replies 6 ·
Replies
6
Views
2K
Wondering if these two First Linear Order IVPs are correct
  • · Replies 2 ·
Replies
2
Views
2K
Finding Critical Points for f(x, y) = sinx + siny + cos(x+y)
  • · Replies 2 ·
Replies
2
Views
8K
How Do I Solve Trig Equations with Exact Values in a Given Domain?
  • · Replies 5 ·
Replies
5
Views
2K