- #1
brizer
- 8
- 0
The problem: The y-intercept of the line tangent to y=(x4-2x2-8)ecosx2 at x=1 is (a) -15.499 (b) -25.999 (c) -41.448 (d) 15.449 (e) 25.99
To find the y-intercept I have to find the whole equation of the line
y=f(1)
m=f'(1)
x=1
b=??
My problem is that I don't think I got the the derivative of f(x) right.
I know you have to apply the product rule and the chain rule, but I don't know if the chain rule should be applied to ecosx2. I came up with this:
(4x3-4x)ecosx2 + (x4-2x2-8)ecosx2(-sinx2)(2x)
then y=-15.4487
m =15.1465
and b=-1.020
the intercept doesn't equal any of the given answers, but y= answer a. However, if I use f'(x)= (4x3-4x)ecosx2 + (x4-2x2-8)ecosx2, I get b=1. What did I do wrong?
To find the y-intercept I have to find the whole equation of the line
y=f(1)
m=f'(1)
x=1
b=??
My problem is that I don't think I got the the derivative of f(x) right.
I know you have to apply the product rule and the chain rule, but I don't know if the chain rule should be applied to ecosx2. I came up with this:
(4x3-4x)ecosx2 + (x4-2x2-8)ecosx2(-sinx2)(2x)
then y=-15.4487
m =15.1465
and b=-1.020
the intercept doesn't equal any of the given answers, but y= answer a. However, if I use f'(x)= (4x3-4x)ecosx2 + (x4-2x2-8)ecosx2, I get b=1. What did I do wrong?