As shown in the figure, it is known that ray DE intersects with X axis and Y axis at point D (3 3,0) and point E (0 0,4) respectively. The moving point C starts from the point M (5 5,0) and moves left along the X axis at a constant speed of 1 unit length/second, while the moving point P starts from the point d and moves at 1 unit length.

(1) Please use an algebraic expression containing t to express the coordinates of point C and point P;

(2) A circle with a radius of 1/2 t (one-half t) with a center at point C intersects with the X axis at two points A and B (point A is on the left side of point B) to connect PA and Pb.

(1) When it has something in common with Ray De, find the value range of t;

② When △PAB is an isosceles triangle, find the value of t. 。

Supplement to the question: