In exercise, find the derivative of the function.
y = 24e-1.4t

Step-by-step explanation:

take derivative with respect to t

derivative of e^t is e^t

derivative of -1.4t is -1.4

Apply chain rule

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4

the surface area is 124cm²

step-by-step explanation:

length: 4cm

width: 9cm

height:   2cm