Answer-If P . cos θ + Q . sin θ = 8 and P . sin θ - Q . cos θ = 5, what is the value of (P² + Q²)?

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Given, P . cos   Q . sin   8   P . cos   Q . sin   2PQ . sin  . cos   64    i  Also given, P . sin  - Q . cos   5   P . sin   Q . cos  - 2PQ . sin  . cos   25    ii  Adding equations i and ii  P  Q  89

If P . cos θ + Q . sin θ = 8 and P . sin θ - Q . cos

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