Graph analysis with trig involved

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SUMMARY

The discussion focuses on the analysis of the function y = sin(2x) - 2sin(x) through calculus techniques. The user successfully derived the first and second derivatives, specifically 2cos(2x) - 2cos(x) and -4sin(2x) + 2sin(x), respectively. However, they seek clarification on finding the roots of these derivatives to determine local minima, maxima, and inflection points. The user questions the validity of an inflection point at zero and the continuity and differentiability of the original function.

PREREQUISITES
  • Understanding of calculus concepts, specifically derivatives and their applications.
  • Familiarity with trigonometric functions and identities, particularly the double angle formulas.
  • Knowledge of finding roots of equations and analyzing function behavior.
  • Basic understanding of continuity and differentiability in mathematical functions.
NEXT STEPS
  • Learn how to apply the double angle formula for trigonometric functions in calculus.
  • Study methods for finding roots of trigonometric derivatives using numerical or analytical techniques.
  • Research the criteria for determining local minima, maxima, and inflection points in calculus.
  • Explore the concepts of domain and range for trigonometric functions and their transformations.
USEFUL FOR

Students studying calculus, particularly those focusing on trigonometric functions and their derivatives, as well as educators seeking to enhance their teaching methods in mathematical analysis.

airportman92
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Homework Statement


given: y=sin2x-2sinx


Homework Equations





The Attempt at a Solution



i already found the roots of the equation, i also found the first and second derivatives which are 2cosx2-2cosx and -4sin2x+2sinx. however, i do not know how to find the roots for these equations in order to do mins and maxes and inflection pt. is it true that the inflection piont is zero, because that's how someone said to do it, but would that mean no concavity at all? and the original is differentiable and continuous correct? also, how wouuld i find the domain and range of this?
 
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For the first derivative, use the double angle formula

cos2x=2cos2x-1 = 1-2sin2x

Solve for x and sub that into the expression for y''.
 

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