Step-by-step explanation:
Using ∆ law of vector addition,
PR→=PQ→+QR→PR→=PQ→+QR→ - (i)
Also,
RP→=RS→+SP→RP→=RS→+SP→ - (ii)
Taking LHS,
=PQ→+QR→+RS→+SP→=PQ→+QR→+RS→+SP→
[Put value of PR→=PQ→+QR→PR→=PQ→+QR→ from equation (i) ]
=(PR→)+RS→+SP→=(PR→)+RS→+SP→
[Put value of RP→=RS→+SP→RP→=RS→+SP→ from equation (ii) ]
=PR→+RP→=PR→+RP→
=PR→−PR→=PR→−PR→
=0=0
RHS
