Rewrite the given function so that we can proceed with the power rule instead of the quotient rule.
Take the derivative of the given function. The derivative of a constant is zero.
`f'(t) = 4t^(-2) = 4/t^2`
Substitute `(t,f(t)) = (4,1)` .
`f'(4)=4/(4^2) = 4/16 = 1/4`
The derivative, or the slope, at the point is one-fourth.
Graph the derivative function and check the value at t=4. It appears to be about 1/4.