Evaluate the approximate tangent slope to f(x)=x^3/8 when x=4

Answer 1

If you mean f(x)=x^(3/8), then the slope at any x is

f'(x) = 3/8 x^(-5/8)

So, when x=4, f'(4) = 3/8 * 4^(-5/8) = 0.157

Answer 2

No. Sorry it's actually f(x)=(x^3)/8 when x=4

Answer 3

d/dx (1/8) x^3 = (1/8) d/dx x^3

= (1/8) (3 x^2)

= (3/8) x^2

when x = 4

= (3/8)(16)

= 6

Answer 4

AT last someone who meant what she wrote, rather than just being careless with parentheses.

However, I'm surprised that given my solution, you did not just fix my function and apply the same logic.

Answer 5

Thanks both of you!!!