# Math Help - Find the tangent line

1. ## Find the tangent line

1. y = xe^x - 1 at x = 0

My solution:

f^1(x) = e^x+ xe^x
f^1(0) = e^0+ 0e^0
=1

Therefore,

y-(-1) = 1(x-0)
y = x - 1

2. y = x Inx at x = 1

My solution:

f^1(x) = x(1/x) + Inx
= In x
f^1(1) = In 1
= 0

Therefore,

y-0 = 0(x-1)
y= 0

Addition question... how can I use math symbols in the forum... I mean the real symbols not like ^ sqrt these kind thing

2. Your first one is fine, but:

Originally Posted by jkami
2. y = x Inx at x = 1

My solution:

f^1(x) = x(1/x) + Inx
= In x
f^1(1) = In 1
= 0
$f'(x) = x\left(\frac1x\right)+\ln x=\frac xx+\ln x=1+\ln x,\,x>0$

So $f'(1) = 1 + \ln1 = 1\text.$