You have the following expression:
To verify the identity, you have that the left side of the equation becomes:
(1 + cosx)(1 - cosx) = (1 - cos^2 x)
because of the product of an expression by its conjugate result in a difference of squares. Or simplfy by expanding the factors and simplying.
Next, you have:
1 - cos^2 x = sin^2 x
because the Pythagorean identity.
Then, the identity is verified.
The function which has range (2, infinity) from the provided function is y = 5ˣ +2. Option 4 is correct.
<h3>What is range of function?</h3>Range of a function is the set of all the possible output values which are valid for that function.
The function whose range is (2, ∞) has to be find out.
The first function given in the problem is,
This function has the periodic function with period of logarithmic function and the range of this function is all the real number. This is not the correct option.
The second function given in the problem is,
This function has the periodic function with period of logarithmic function and the range of this function is all the real number. This is not the correct option.
The fourth function given in the problem is,
This function is translated 5 units up to the function 5ˣ which has the range (0,∞).
Thus, the range of this function is (2, ∞).
Hence, the function which has range (2, infinity) from the provided function is y = 5ˣ +2. Option 4 is correct.
Learn more about range of the function here;