So, I have been working problems finding the derivative of polynomial equations. I am having some problems, however. The problem is as follows:

Find the line tangent to the curve of Y = 4th root of X, on the point (1, 1).

This is my working of the problem...

y= 4th root of x

y' = x ^ 1/4 = 1/4 x ^ -3/4 = m

therefore, the line tangent to this should be Y - Y1 = m(x - x1) so:

y - 1 = 1/4 x ^ -3/4(x - 1)

y - 1 = 1/4 x ^ 1/4 - 1/4x ^ -3/4

y = 1/4 x ^ 1/4 - 1/4x ^ -3/4 + 1

y = 1/4x + 1 <<<<<<

So by my calculations the line equation should be y = 1/4x + 1. However the book has the answer as y = 1/4x + 3/4. Where have I gone wrong? I don't see it.