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If P = 7 + 4√3 and PQ = 1, then what is the value of (1/P2) + (1/Q2)?
- A148
- B189
- C194
- D204
Answer not set
Discussion 1
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CCommunity
Here from PQ = 1 we can write (1/P2) + (1/Q2) = (1/P2) + (P2)
P = 7 + 4√3 and P2 = 97 + 56√3
And by rationalising the denominator in 1/P2 = 1/ (97 + 56√3) = 97 – 56√3
⇒ (1/P2) + (1/Q2) = (1/P2) + (P2) = 97 – 56√3 + 97 + 56√3 = 194
∴ The value of (1/P2) + (1/Q2) = 194
P = 7 + 4√3 and P2 = 97 + 56√3
And by rationalising the denominator in 1/P2 = 1/ (97 + 56√3) = 97 – 56√3
⇒ (1/P2) + (1/Q2) = (1/P2) + (P2) = 97 – 56√3 + 97 + 56√3 = 194
∴ The value of (1/P2) + (1/Q2) = 194