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If T(p), T(q) and T(r) of a G.P. are +iv...

If `T_(p), T_(q) and T_(r)` of a G.P. are `+`ive numbers a, b, c respectively, the vectors
`alpha =ilog a+jlogb+klogc`,
`beta =i(q-r)+j(r-p)+k(p-q)`
are perpendicular . True and False ?

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The correct Answer is:
To determine whether the vectors \(\alpha\) and \(\beta\) are perpendicular, we need to check if their dot product is zero. Let's break down the solution step by step. ### Step 1: Define the vectors Given: - \( T_p = a \) - \( T_q = b \) - \( T_r = c \) The vectors are defined as: \[ \alpha = i \log a + j \log b + k \log c \] \[ \beta = i(q - r) + j(r - p) + k(p - q) \] ### Step 2: Calculate the components of \(\beta\) From the definitions of \(T_p\), \(T_q\), and \(T_r\), we can express \(q - r\), \(r - p\), and \(p - q\) in terms of logarithms: - \(q - r = \log b - \log c = \log \left(\frac{b}{c}\right)\) - \(r - p = \log c - \log a = \log \left(\frac{c}{a}\right)\) - \(p - q = \log a - \log b = \log \left(\frac{a}{b}\right)\) Thus, we can rewrite \(\beta\) as: \[ \beta = i \log \left(\frac{b}{c}\right) + j \log \left(\frac{c}{a}\right) + k \log \left(\frac{a}{b}\right) \] ### Step 3: Compute the dot product \(\alpha \cdot \beta\) The dot product of two vectors \(\alpha\) and \(\beta\) is given by: \[ \alpha \cdot \beta = \log a \cdot \log \left(\frac{b}{c}\right) + \log b \cdot \log \left(\frac{c}{a}\right) + \log c \cdot \log \left(\frac{a}{b}\right) \] ### Step 4: Simplify the dot product Substituting the logarithmic expressions: \[ \alpha \cdot \beta = \log a \cdot (\log b - \log c) + \log b \cdot (\log c - \log a) + \log c \cdot (\log a - \log b) \] Expanding this: \[ = \log a \log b - \log a \log c + \log b \log c - \log b \log a + \log c \log a - \log c \log b \] ### Step 5: Combine like terms Notice that: - \(\log a \log b\) and \(-\log b \log a\) cancel each other. - \(\log b \log c\) and \(-\log c \log b\) cancel each other. - \(\log c \log a\) and \(-\log a \log c\) cancel each other. Thus, we find: \[ \alpha \cdot \beta = 0 \] ### Conclusion Since the dot product \(\alpha \cdot \beta = 0\), the vectors \(\alpha\) and \(\beta\) are indeed perpendicular. ### Final Answer **True**: The vectors \(\alpha\) and \(\beta\) are perpendicular. ---
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ML KHANNA-ADDITION AND MULTIPLICATION OF VECTORS -Problem Set (2) (TRUE AND FALSE)
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  8. Prove (i) r = (r.i) i+(r.j)j+(r.k)k (ii) ixx(axxi) +jxx(axxj)+kx...

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  16. For any two vectors u and v, find if (1+|u|^(2))(1+|v|^(2)) = (1-u....

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  17. Using dot product of vectors; prove that a parallelogram; whose diagon...

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  18. If AC and BD are the diagonals of a quadrilateral ABCD, prove that its...

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