00:01
So here it is asked to find the coefficient of x -rays to 9, y -raise to 3 in the expansion of different questions are given.
00:08
So the question is asked to find coefficient of coefficient of x -raise to 9, y to the power 3.
00:19
So this is the term that we would have to find.
00:22
The coefficient of this term is what we would have to find.
00:25
And there are different expressions given as the first expression was x plus y whole raise to 12.
00:29
The first one was x plus y whole raise to n now first thing that we would have to know for the one equation that we would have to know to solve this kind of equation is if we have a polynomial like a plus b whole raise to n that the general formula to find this uh or the terms of this polynomial is uh in this polynomial t r plus one that is r plus one the term will be equal to ncr a raise to a raise to n b raised to n minus r so this is the equation to find the terms of a polynomial having higher degrees so using this equation we can just find the answer to this question we are asked so it here it is asked to find the coefficient of x raised to 9, y raise to 3.
01:34
So just by comparing to this equation, we can see that instead of x, we have a over here.
01:40
So the power of a was n.
01:42
So here n is equal to, sorry for this, the equation was, so the equation was not like this.
01:53
Here it is r and here it is n minus r.
01:55
This is the equation...