Question

5. Which of the following statements is FALSE about the function f(x) = cos x? Explain your reasoning.

A) f(x) = f(-x)
B) f(x) has a y-intercept of 1.
C) The x-axis represents the cosine ratio.
D) f(146π) = 1

Answer 1

The false statement is option B, which claims that the function f(x) = cos x has a y-intercept of 1.

The y-intercept of a function is the point at which it intersects with the y-axis, which corresponds to the input value x = 0. For the function f(x) = cos x, we have:

f(0) = cos 0 = 1

Therefore, the function intersects the y-axis at the point (0,1), which means that the y-coordinate of the point of intersection is 1, not the function's y-intercept.