Practicing Success
Practicing Success
CUET Preparation Today
If a + b = p, ab = q, then $(a^4 + b^4)$ is equal to : |
$p^4 - 2p^2q^2 + q^2$ $p^4 - 4p^2q^2 + 2q^2$ $p^4 - 4p^2q + q^2$ $p^4 - 4p^2q + 2q^2$ |
$p^4 - 4p^2q + 2q^2$ |
Given, a + b = p, ab = q We know that, (a + b)2 = a2 + b2 + 2ab So, Squaring on both sides, p2 = (a2 + b2) + 2q (a2 + b2) = p2 - 2q Then, (a4 + b4) = (a2 + b2)2 - 2a2b2 = (p2 - 2q)2 - 2q2 = p4 - 4p2q + 2q2 |
