Prove that $\cos\left(x\right)^3-3\cos\left(x\right)=3\cos\left(x\right)\sin\left(x\right)$ is not an identity

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Final answer to the problem

The equation is not an identity

Step-by-step Solution

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  • Verify if true (using arithmetic)
  • Express in terms of sine and cosine
  • Simplify
  • Simplify into a single function
  • Express in terms of Sine
  • Express in terms of Cosine
  • Express in terms of Tangent
  • Express in terms of Cotangent
  • Express in terms of Secant
  • Express in terms of Cosecant
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To prove that an equation is not an identity, we only need to find one input at which both sides of the equation result in different values

Since we're dealing with trig functions, we can try with different angles as input, such as: $0^{\circ}, 30^{\circ}, 60^{\circ}, 90^{\circ}, 180^{\circ}...$

Learn how to solve differential calculus problems step by step online.

Since we're dealing with trig functions, we can try with different angles as input, such as: $0^{\circ}, 30^{\circ}, 60^{\circ}, 90^{\circ}, 180^{\circ}...$

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Learn how to solve differential calculus problems step by step online. Prove that cos(x)^3-3cos(x)=3cos(x)sin(x) is not an identity. To prove that an equation is not an identity, we only need to find one input at which both sides of the equation result in different values. If we try with the following value. After substituting the value and simplify on the left side, we get. After substituting the value and simplify on the right side, we get.

Final answer to the problem

The equation is not an identity

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Main Topic: Differential Calculus

The derivative of a function of a real variable measures the sensitivity to change of a quantity (a function value or dependent variable) which is determined by another quantity (the independent variable). Derivatives are a fundamental tool of calculus.

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