Limit question. Have solution, need to know how to get it.

  • Thread starter Thread starter bored2death97
  • Start date Start date
  • Tags Tags
    Limit
Click For Summary
SUMMARY

The discussion revolves around a mathematical problem involving the manipulation of trigonometric identities, specifically the expression involving (cosx + 1). The user initially struggled to understand the derivation of this term in the context of a solution manual. After further analysis, they realized that the term was introduced by multiplying by a form of 1, specifically (cos(x) + 1)/(cos(x) + 1), which facilitated the simplification of the equation. The relevant equations discussed include the sine addition formula and the Pythagorean identity.

PREREQUISITES
  • Understanding of trigonometric identities, specifically sine and cosine functions.
  • Familiarity with algebraic manipulation of fractions.
  • Knowledge of the sine addition formula: sin(x+y) = sinx cosy + cosx siny.
  • Basic understanding of the Pythagorean identity: sin²(x) + cos²(x) = 1.
NEXT STEPS
  • Study the derivation and applications of the sine addition formula in various problems.
  • Practice algebraic manipulation techniques involving fractions and trigonometric expressions.
  • Explore advanced trigonometric identities and their proofs.
  • Review problem-solving strategies for trigonometric equations in calculus.
USEFUL FOR

Students studying trigonometry, educators teaching mathematical concepts, and anyone looking to enhance their understanding of trigonometric identities and algebraic manipulation.

bored2death97
Messages
10
Reaction score
0

Homework Statement



I was working on a problem in my book, and I didn't know how to answer the question. So I looked at the solution manual. and it had this

http://imgur.com/VF4yl

I do not know where the (cosx + 1) on the bottom came from. Any ideas? Please explain.

Homework Equations



sin(x+y)= sinx cosy + cosx siny

The Attempt at a Solution



I get the top part though, you factor out the 2, multiply the cos and sin then it becomes sin(x+y) sort of thing.Ok, nevermind, I am sorry, I didn't realize they factored out the cosx-1 and then multiplied by (cosx +1)/(cosx+1) So I got it now.
 
Physics news on Phys.org
bored2death97 said:

Homework Statement



I was working on a problem in my book, and I didn't know how to answer the question. So I looked at the solution manual. and it had this

http://imgur.com/VF4yl

I do not know where the (cos-1) on the bottom came from. Any ideas? Please explain.
They multiplied by 1 in the form
$$ \frac{cos(x) + 1}{cos(x) + 1}$$
bored2death97 said:

Homework Equations



sin(x+y)= sinx cosy + cosx siny
One that is relevant to the question you asked is:
sin2(x) + cos2(x) = 1
bored2death97 said:

The Attempt at a Solution



I get the top part though, you factor out the 2, multiply the cos and sin then it becomes sin(x+y) sort of thing.
 

Similar threads

  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
9
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K