3-20 할리데이 11판 솔루션 일반물리학

$$\begin{cases} r=5.60\ut{km}\\ \theta=27.0\degree \end{cases}$$ $$\vec r = 5.6\cos27\degree\i+5.6\sin27\degree\j,$$ $$\begin{aligned} \Ans&=r_x+r_y\\ &=5.6\cos27\degree+5.6\sin27\degree\\ &\approx 7.531983333996322\ut{km}\\ &\approx 7.53\ut{km}\\ \end{aligned}$$