Is Cos2x the Same as Cos^2(x) in the Equation Cos2x + Cosx + 1 = 0?

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Homework Help Overview

The discussion centers around the equation cos(2x) + cos(x) + 1 = 0 and the clarification of whether cos(2x) is equivalent to cos²(x). Participants are exploring trigonometric identities and their implications in solving the equation.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants are questioning the relationship between cos(2x) and cos²(x) and discussing the use of trigonometric identities. Some are attempting to rewrite the equation in a more manageable form, while others are unsure about how to express 1 in terms of sine and cosine.

Discussion Status

There is an ongoing exploration of trigonometric identities, with some participants suggesting the use of double angle identities. Guidance has been offered regarding the potential simplification to a quadratic equation, but no consensus has been reached on the approach to take.

Contextual Notes

Participants note that the answers are in radians, which may influence their approach to solving the equation. There is also a lack of clarity on how to manipulate the equation effectively, indicating potential gaps in foundational knowledge.

aisha
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Solve please give me some help

how would you solve this question cos2x+cosx+1=0? The cos2x is throwing me off is that the same as cos^2x? Its multiple choice and all the answers are in radian how come?
 
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1. cos(a + b) = cos(a)cos(b) - sin(a)sin(b).
2. Do you know how to write 1 in terms of sin and cos?
 
AKG said:
1. cos(a + b) = cos(a)cos(b) - sin(a)sin(b).
2. Do you know how to write 1 in terms of sin and cos?

no i don't please help me
 
[tex]\sin^{2}x + \cos^{2}x = 1[/tex]
 
cos2x is not the same as cos^2x. Use a double angle identity for that one.
 
On normal basis,u should end up with a simple quadratic equation is "\cos x"...That won't be 2 hard to solve...

Daniel.
 

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