Practicing Success
What is the coefficient of y2 in the expansion of $(\sqrt{2}y^2 - 5\sqrt{3})^3$ ? |
$-225\sqrt{2}$ $-30\sqrt{3}$ $225\sqrt{2}$ $30\sqrt{3}$ |
$225\sqrt{2}$ |
We know that, (a – b)3 = a3 – b3 – 3a2b + 3ab2 Given, (\(\sqrt { 2}\)y2 – 5\(\sqrt { 3}\))3 = (\(\sqrt { 2}\) y2)3 – (5\(\sqrt { 3}\))3 – 3.( \(\sqrt { 2}\) y2)2.(5\(\sqrt { 3}\)) + 3.( \(\sqrt { 2}\) y2)(5\(\sqrt { 3}\))2 = 2\(\sqrt { 2}\) y6 – 375\(\sqrt { 3}\) 3 – 30\(\sqrt { 3}\) y4 + 225\(\sqrt { 2}\) y2 Coefficient of y2 = 225\(\sqrt { 2}\) |