A^2+b^2=c^2
42^2+b^2=58^2
1764+b^2=3364
b^2=3364-1764
b^2=1600
square root b^2=square root 1600
b=40 inches
First of all, we need to know what a function is.
A function is a binary relation between two sets that
F(x)=-9/x which is equal to:
f(x)=-9x^(-1) So the power rule for differentiation is used...
Power rule: f(x)=x^e, df/dx=ex^(e-1) so:
df/dx=-9(-1)x^(-1-1)
df/dx=9x^(-2) or if you prefer...
df/dx=9/x^2
df/dx(6)=9/36=1/4
I believe it's one of the four in photo.
I think the answer is the third one
