vector section formula
Answers
Step-by-step explanation:
represented by position vectors OP→ and OQ→, respectively, with respect to origin O. We can divide the line segment joining the points P and Q by a third point R in two ways:
Internally
Externally
If we want to find the position vector OR→ for the point R with respect to the origin O, then we should take both the cases one by one.
Case 1 – R Divides Segment PQ Internally
Take a look at Fig. 1 again. In this figure, if the point R divides PQ→ such that,
mRQ→ = nPR→ … (1)
where ‘m’ and ‘n’ are positive scalars, then we can say that R divides PQ→ internally in the ratio m:n. Now, from the triangles ORQ and OPR, we have
RQ→ = OQ→ – OR→ = b⃗ – r⃗
And, PR→ = OR→ – OP→ = r⃗ – a⃗
Therefore, replacing the values of RQ→ and PR→ in equation (1) above, we get
m(b⃗ – r⃗ ) = n(r⃗ – a⃗ )
Or, r⃗ = mb⃗ +na⃗ m+n … (2)
Hence, the position vector forula of the point R which divides PQ internally in the ratio m:n is,
OR→ = mb⃗ +na⃗ m+n
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