Question

If O = (0, 0, 0), P = (4, 3, -5), Q = (-2, 1, -8), $\cos\angle POQ = \frac{a}{\sqrt{b}\sqrt{c}}$ and b > c then b - c =

• A. 19
• B. $\sqrt{69} - \sqrt{50}$
• C. -19
• D. 17

Answer 1

Answer: (A)

19

Answer 2

D.r?? of OP = (4,3,-5), D.r?? of OQ = (-2,1 - 8) $cos \angle {OPQ} = \frac{-8+3-40}{\sqrt{50 } .\sqrt{69}}$ b - c = 69 - 50 b - c = 19