Trig functions, finding co-ordinates

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Homework Help Overview

The problem involves finding the coordinates of the intersection point B between the functions f(x)=sin(2x) and g(x)=cos(x) within a specified domain.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to equate the two functions to find the intersection points and questions whether their approach is correct. Other participants inquire about the specific range for solutions and suggest the existence of multiple intersection points.

Discussion Status

The discussion is ongoing, with participants exploring different aspects of the problem, including the need for a specific range and the potential use of trigonometric identities. No consensus has been reached regarding the method to find the coordinates of point B.

Contextual Notes

The domain for x is specified as xE[0;270], and it is noted that the functions intersect at point A(30, 0.87) and potentially at point B.

TheRedDevil18
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Homework Statement



I have a graph with the functions f(x)=sin2x and g(x)=cosx. The 2 graphs intersect at point B. They want me to find the co-ordinates of B.

Homework Equations





The Attempt at a Solution



Must I equate the two graphs?

sin2x = cosx
2x = 90-x, 3x = 90, x=30 or 2x = 180-(90-x), x=90

It doesn't seem right, is their any other steps?
 
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Aren't you given any specific range within which you want the solution, both the graphs intersect at many points.
 
they say that f and g intersect at A(30:0.87) and B.
the domain is xE[0;270].
Thats all that is given.
 
Do you know a trig identity for sin(2x)?
 

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