Help with 30 please. thanks.​

See Below.

Step-by-step explanation:

We have the equation:

And we want to show that:

Instead of differentiating directly, we can first square both sides:

We can find the first derivative through implicit differentiation:

Hence:

And we can find the second derivative by using the quotient rule:

Substitute:

Simplify:

Combine fractions:

Simplify:

Simplify:

Q.E.D.

7 ft 6 in means 7 1/2, because 6 in is 1/2 of a foot. 7 ft 8 in means 7 2/3 because 8 in is 2/3 of a foot. 23/3 = 7 2/3. 15/2 = 7 1/2.

23/3   *   15/2   = 57 1/2

step-by-step explanation:

the square root of what number? if you add that, then someone will probably answer the question.