The $x ^ { \prime } y ^ { \prime }$

Multiple Choice

The $x ^ { \prime } y ^ { \prime }$ -coordinate system has been rotated $\theta$ degrees from the $x y$ -coordinate system.The coordinates of a point in the $x y$ -coordinate system are given.Find the coordinates of the point in the rotated coordinate system.​ $\theta = 45 ^ { \circ }$ , $( 10,10 )$ ​

A) $( - 5 \sqrt { 2 } , 0 )$
B) $( 5 \sqrt { 2 } , 0 )$
C) $( - 10 \sqrt { 2 } , 0 )$
D) $( 6 \sqrt { 2 } , 0 )$
E) $( 10 \sqrt { 2 } , 0 )$