Chapter 11 - Vectors and the Geometry of Space - 11.7 Exercises - Page 809: 1

$(x,y,z)=(-7,0.5)$

Relationship between cylindrical co-ordinates and rectangular co-ordinates is: $$x= r \cos \theta ; y= r \sin \theta; z=z ~~~(1)$$ We are given that $r=-7$ and $\theta=0^{\circ}$ Plug these values in Equation (1) to obtain: $$x=-7 \cos 0^{\circ} ; y= -7 \sin 0^{\circ}; z=5$$ This implies that $x= -7; y=0; z=5$ So, our solution is: $(x,y,z)=(-7,0.5)$