January 28, 2015

Homework Help: Math (Calculus 121)

Posted by drwls on Monday, February 19, 2007 at 9:02pm.

The derivative tells you the slope at any point.
df/dx = 8 x^3 - 12 x
When x = 3, the slope is
m = 8*27 - 36 = 180

and the equation of the tangent line is

(y - 228) = 180*(x - 3)
y = 180 x - 540 + 228 = 180 x - 312

wow, that was absolutely correct (i just plugged it into webassign), thanks a lot!!

please just help me to understand the last part though for the test, where did you get the (y-228) = 180*(x-3)?

Find the equation of the line that is tangent to the graph of f(x) = 2x4 - 6x2 + 120 at the point (3, 228).


The equation for a line with slope m through points x = a and y = b is
(y- b)= m (x - a)

That is where the formula came from.

Answer this Question

First Name:
School Subject:

Related Questions

Calculus derivative - find the slope m and an equation of the tangent line to ...
Math (Calculus 121) - Consider the following function. f(x) = 7x3 + x2 - 0.08x...
Calculus - How do you find Altitude and slope slope is the derivative of a ...
Math - 1. The slope of the tangent line to a function at a point is equivalent ...
AP calculus - Find the equation of the normal to the curve f(x) = 3cos(2x) at ...
Calculus (pleas help!) - Find the slope of the tangent line to the ellipse x^2/...
Algebra - I have an assignment that asks me to write an equation in slope-...
math - What is the definition of the slope of a curve at a point x=a? Formal ...
calculus - find the point on the graph of the given function at which the slope ...
calculus - *find the slope of y= 4/x +6 at the point (8,2) *evaluate the ...