Define rectangular components of vector.
4. If θ is the angle made by the vector A→ with an x-axis, then
Ax=AcosθandAy=Asinθ
5. Using the triangle law of vector addition, we can write A=→Axˆi+Ayˆj,whereˆiandˆjareunitcectorsalongxandyaxisresp.
Thus A=→Acosθˆi+Asinθˆj,