00:01
We're given the fourth degree polynomial x to the fourth plus a x cubed plus bx squared plus cx plus d.
00:13
We also know that the tangent line when x is equal to 0 is y equals 2x plus 1 and the tangent line when x equals 2 minus 3x.
00:28
Now from those two tangent lines we can derive some information here.
00:37
Y prime when x is equal to 0 must equal to as the slope of that tangent line is 2.
00:48
Furthermore we know that at x equals 0 it goes through the point 0 1 plugging 0 into that tangent line.
01:00
Let's get the same information from the tangent line when x is equal to 1.
01:06
Y prime must equal negative 3, and we know when x is 1, it will go through the point negative 1.
01:21
All right, let's go ahead and derive our polynomial.
01:25
We know that y prime will equal 4x cubed plus 3a x squared plus 2ax squared plus 2.
01:34
B x plus c.
01:38
Let's go ahead and find what y prime at x equals 0.
01:44
Plugging in 0 into our first derivative, everything cancels with the exception of c, so c must equal 2.
01:54
Let's go ahead and do that for the derivative at x equals 1.
02:02
This will give us 4 plus 3a plus 2.
02:09
2b plus c, which we now know as 2, is equal to negative 3...