Describe the transformations required to obtain the graph of the function f(x) from the graph of the function g(x).
-$$f ( x ) = - 2 \cos \frac { \pi x } { 7 } ; g ( x ) = \cos x$$
A) Horizontal stretch by a factor $\frac { 7 } { \pi }$, vertical stretch by a factor of 2 , reflection across $x$-axis
B) Horizontal shrink by a factor $\frac { \pi } { 7 }$ vertical shrink by a factor of $\frac { 1 } { 2 }$, reflection across $y$-axis
C) Horizontal stretch by a factor $\frac { 7 } { \pi }$, vertical stretch by a factor of 2 , reflection across y-axis
D) Horizontal shrink by a factor $\frac { \pi } { 7 }$, vertical stretch by a factor of 2 , reflection across $x$-axis

Question

Quizplus · Accepted Answer

The graph of $f(x)$ is obtained from the graph of $g(x)$ by a horizontal stretch by a factor of $\frac{7}{\pi}$, a vertical stretch by a factor of 2, and a reflection across the $x$-axis.

Describe the Transformations Required to Obtain the Graph of the Function