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| 1. |
If the graph of the function x2 − 4x + log3 a does not cut the real axis, then the least integral value of 'a' is (1) 80 (2) 81 (3) 82 (4) 0 |
| Answer» <p><span style="color:#000000"><span style="font-family:Arial,Helvetica,sans-serif"><strong>Correct option</strong></span></span><strong>(3) 82</strong></p><p><span style="color:#000000"><span style="font-family:Arial,Helvetica,sans-serif"><strong>Explanation:</strong></span></span></p><p><span style="color:#000000"><span style="font-family:Arial,Helvetica,sans-serif">The graph of the function x<sup>2</sup> − 4x + log<sub>3</sub> a </span></span></p><p><span style="color:#000000"><span style="font-family:Arial,Helvetica,sans-serif">does not cut the real axis. </span></span></p><p><span style="color:#000000"><span style="font-family:Arial,Helvetica,sans-serif">⇒ the roots of x<sup>2</sup> − 4x + log<sub>3</sub> a = 0 are imaginary. </span></span></p><p><span style="color:#000000"><span style="font-family:Arial,Helvetica,sans-serif">⇒ log<sub>3</sub> a > 4 ⇒ a > 81</span></span></p><p><span style="color:#000000"><span style="font-family:Arial,Helvetica,sans-serif">⇒ the least integral value of a is 82.</span></span></p> | |