Final answer:
The expressions 6cos(θ) and 4cos(θ) do not require further simplification using trigonometric identities as they are already in their simplest form, representing a scaling of the cosine function.
Step-by-step explanation:
To simplify the expressions 6cos(θ) and 4cos(θ) using identities, we don't actually need to apply any trigonometric identities directly since these are already in simplified form. However, understanding the context of trigonometric identities can be helpful in simplifying more complex expressions.
For example, the double angle identities such as sin(2θ) = 2sin(θ)cos(θ) and cos(2θ) = cos²(θ) - sin²(θ) can be used to simplify expressions involving trigonometric functions at multiple angles.
In the case of the expressions provided, 6cos(θ) and 4cos(θ) are already the simplest forms, indicating a scaling of the cosine function by 6 and 4 respectively.
To ensure the solution is reasonable, always consider the domain and range of trigonometric functions, and if dealing with angles, use radians as the unit of angle measure.