00:01
We can use the formula written to the left derived from the binomial theorem to find specific coefficients in a binomial.
00:09
So if we have x minus 2 over the square root of x to the 10th, which can be written as x plus negative 2 x to the negative 1 half all to the 10th, and we want to find the coefficient of x to the 4th, we can use this formula.
00:29
Normally, if we wanted to find the coefficient of x to the fourth, we could set j equal to 4.
00:35
However, because this binomial has an x in both terms, we can't do this.
00:40
Instead, we need to find the value of j where a to the n minus j comes x to the j equals x to the 4th.
00:52
Now, looking at this equation, we could see that for our equation, x equals x, a equals negative 2 the x to the negative 1 half power and n equals 10.
01:09
Now plugging these in, we get negative 2 to the 10 minus j times x to the negative 1 half power all to the 10 minus j power times x to the j equals x to the 4th.
01:29
Now because we only want to find the coefficient of x to the fourth and this term does not have an exonate, we can disregard it...