00:01
So for this problem, we're going to be using the binomial series in order to expand 1 over the square root of 1 minus x squared.
00:11
So we know that we can simplify this into a term that'll make it better for the binomial series, and that's 1 plus a negative x squared to the negative 1�.
00:25
And knowing the binomial series, all that we can do now is define k to equal a negative 1⁄2.
00:32
And we'll replace x with a negative x squared.
00:38
So when we do that, what we'll end up getting as a result is going to be 1 plus 1 half x squared plus 3 over 2 squared times 2 factorial x to the 4th plus 3 times 2 factorial x to the 4th plus 3 times 5 over 2.
01:06
Two cube times three factorial x to the sixth, and then plus three times five times seven over two to the fourth times four factorial x to the eighth plus and so on.
01:22
So with that in mind, what we're going to end up getting is that this is the same thing as one plus the sum from n equals one because we're skipping the first term to infinity of 1 times 3 times 5 times 7 times dot dot 2n minus 1 and then that's all going to be over 2 to the n times n factorial all times x to the 2n with this in mind um we uh have the binomial series expanded and now we have it simplified to mean this.
02:11
So for part b, we want to use this to find the mclaurin series for the inverse sign of x.
02:21
So since the derivative of the inverse sign of x is that.
02:28
So keep in mind that the derivative of the inverse sign of x is in fact one over the square root of 1 minus x squared...