Question

consider the function y= -2 cos(x- pi). what effect does "-2" have on the basic graph? A) horizontal stretch by the factor 2 then flip over vertical axis b) vertical stretch by factor 2 then flip over horizontal axis c) vertical compression by factor 2 d) horizontal compression by factor 2

Answer 1

The correct option is;

b) Vertically stretches by a factor 2 then flip over horizontal axis

Explanation:

In the function y = -2×cos(x - pi), given that the maximum value of the cosine function is 1 and that the value of the cosine function ranges from +1 to -1, we have that a factor larger than 1, multiplying a cosine function vertically stretches the function and a negative factor flips the function over the horizontal axis by transforming the y-coordinate value from y to -y

Therefore, the factor of -2, vertically stretches the the function by a factor of 2 then flip over horizontal axis.