Question

if p+q+r=√42 and p²+q²+r²=16,find pq+rq+rp

Answer 1

Hey dear here is ur answer************
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We know,

(p+q+r)^2=p^2+q^2+r^2+2(pq+rq+rp)

or,(√42)^2=16+2(pq+rq+rp)

or,42-16=2(pq+rq+rp)

or,pq+rq+rp=13[Ans.]

Hope it will help u@@@@@####