Proving Identities: Compound Angle, Double Angle, Quotient & Reciprocal

  • Thread starter Thread starter Random-Hero-
  • Start date Start date
  • Tags Tags
    identities
Click For Summary
SUMMARY

The discussion focuses on proving two trigonometric identities: (a) cos(x)/(1-sin(x)) = sec(x) + tan(x) and (b) (cos^2(x) + sin(x)cos(x))/tan(x) = 2cos^2(x). The user attempted to apply compound angle formulas, double angle formulas, quotient identities, and reciprocal identities but struggled to complete the proofs. A suggested approach for part (a) involves manipulating the left-hand side to reach the right-hand side by dividing the numerator and denominator by a specific term.

PREREQUISITES
  • Understanding of trigonometric identities, including compound and double angle formulas.
  • Familiarity with quotient and reciprocal identities in trigonometry.
  • Basic algebraic manipulation skills for simplifying expressions.
  • Knowledge of the sine, cosine, secant, and tangent functions.
NEXT STEPS
  • Study the derivation of compound angle formulas in trigonometry.
  • Learn how to apply double angle formulas to simplify trigonometric expressions.
  • Practice manipulating trigonometric identities using quotient and reciprocal identities.
  • Explore examples of proving trigonometric identities for deeper understanding.
USEFUL FOR

Students studying trigonometry, educators teaching trigonometric identities, and anyone looking to enhance their skills in proving mathematical identities.

Random-Hero-
Messages
40
Reaction score
0

Homework Statement



Prove the following identities.

a) cosx/1-sinx = secx + tanx

b) cos^2x+ sinxcosx/tanx = 2cos^2x


The Attempt at a Solution



Well what I tried doing was substituting the appropriate compound angle formulas, double angle formulas, quotient identities, and reciprocal identities, but I just can't seem to solve it all the way (if that's what "prove" means in the first place anyways)

Anyone have any idea how I'd go about solving them? This is what I have so far.

a) cosx/1-sinx = 1/cosx + sinx/cosx

b) I haven't started yet :/
 
Physics news on Phys.org
to prove part a) you should start with one side of the equation and manipulate it to arrive at the other side of the equation.

I'd begin with the left hand side. To get started, divide numerator and denominator by a certain term (do you see which term?)
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
Replies
5
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 8 ·
Replies
8
Views
7K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 8 ·
Replies
8
Views
6K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K