In the expansion of $(a-b)^{n},n\ge 5$, if the sum of the $5^{th}$ and $6^{th}$ terms is zero, then $a/b$=

The number of terms in the expansion of $\left\{ ( \sqrt {2}x +\sqrt {3} y)^{10} - ( \sqrt {2} x - \sqrt {3} y)^{10} \right\}$ is-

দৃশ্যকল্প- $: f(\mathrm{y})=\mathrm{y}-1$.

দৃশ্যকল্প-২ : $(1+a y)^{m}$ একটি দ্বিপদী রাশি।

The number of terms in the expansion of $\left\{ ( ( 5x + 2y)^7 + (5x -2y)^7 \right\}$ is

After simplification, the total number of terms in the expansion of $( x + \sqrt { 2 } ) ^ { 4 } + ( x - \sqrt { 2 })^4$ is-