y=x^3 + 2x using dy/dx?

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y=x^3 + 2x using dy/dx?

Using the formula y=x^3 + 2x, I am to using deriatives, find the equation of the tangent line. Any help would be appreciated!

2006-11-30 08:38:10 · 3 answers · asked by Knight_of_Sarcasm 2 in Science & Mathematics ➔ Mathematics

3 answers

equation of the tangent of the line is the derivative of the line

dy/dx = 3x^2 + 2

2006-12-01 00:04:45 · answer #1 · answered by ludacrusher 4 · 0⤊ 0⤋

dy/dx = 3x^2 + 2.
The equation of a line is (y-y1) = m(x-x1)
So, the find the tangent line going through x1=a:
y1 = a^3 + 2a
m = 3a^2 + 2

So y - (a^3 + 2a) = (3a^2 + 2)(x-a).
You could expand and rearrange if you want.

2006-11-30 16:42:25 · answer #2 · answered by stephen m 4 · 0⤊ 0⤋

(dy/dx) = (3 x^2 )+ 2

2006-11-30 16:40:50 · answer #3 · answered by James 1 · 0⤊ 0⤋