A baseball is hit along the third base line with a speed of 100 ft/s. At what rate is the balls distance from first base changing when it crosses third base?

Solution :

From the triangle,

Now differentiating w.r.t "t", we get

        [chain rule]

But given that = 100 ft/s

When all the ball crosses the third base, this means that s = 90. So substituting the value of s and  in , we get

    = 70.710 ft/s    

cheater

step-by-step explanation:

i think the answer is a.( -3, -1 )