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The value of x, for which the matrix A = \(\begin{bmatrix}e^{x - 2} &e^{7 + x} \\[0.3em]e^{2 + x}&e^{2x + 3}\end{bmatrix}\) is singular is …(a) 9(b) 8 (c) 7 (d) 6 |
Answer» (b) 8 Given A is a singular matrix ⇒ |A| = 0 (i.e.) \(\begin{bmatrix}e^{x - 2} &e^{7 + x} \\[0.3em]e^{2 + x}&e^{2x + 3}\end{bmatrix}\)= 0 ⇒ ex - 2.e2x + 3 – e2 + x.e7 + x = 0 ⇒ e3x + 1 – e9 + 2x = 0 ⇒ e3x + 1 = e9 + 2x ⇒ 3x + 1 = 9 + 2x 3x – 2x = 9 – 1 ⇒ x = 8 |
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