Questions: Consider the formula: K=A^3 B^5/10. Given that both A and B vary with respect to t; find dK/dt.
(A) dK/dt=3 A^2 B^5/10 dA/dt+A^3 B^4/2 dB/dt
B dK/dt=3 A^2 B^5/10
C dK/dt=3 A^2 B^4/2 dA/dt dB/dt
D dK/dt=A^3 B^5/10 dA/dt+A^3 B^5/10 dB/dt
E dK/dt=3 A^3 B^5/10 dA/dt+A^3 B^5/2 dB/dt
Transcript text: Consider the formula: $K=\frac{A^{3} B^{5}}{10}$. Given that both $A$ and $B$ vary with respect to $t$; find $\frac{d K}{d t}$.
(A) $\frac{d K}{d t}=\frac{3 A^{2} B^{5}}{10} \frac{d A}{d t}+\frac{A^{3} B^{4}}{2} \frac{d B}{d t}$
B $\quad \frac{d K}{d t}=\frac{3 A^{2} B^{5}}{10}$
C $\quad \frac{d K}{d t}=\frac{3 A^{2} B^{4}}{2} \frac{d A}{d t} \frac{d B}{d t}$
D $\frac{d K}{d t}=\frac{A^{3} B^{5}}{10} \frac{d A}{d t}+\frac{A^{3} B^{5}}{10} \frac{d B}{d t}$
E $\quad \frac{d K}{d t}=\frac{3 A^{3} B^{5}}{10} \frac{d A}{d t}+\frac{A^{3} B^{5}}{2} \frac{d B}{d t}$
Solution
Solution Steps
To find \(\frac{dK}{dt}\) for the given formula \(K = \frac{A^3 B^5}{10}\), we need to use the chain rule for differentiation. Since both \(A\) and \(B\) are functions of \(t\), we will differentiate \(K\) with respect to \(t\) by treating \(A\) and \(B\) as functions of \(t\).
Differentiate \(K\) with respect to \(A\) and multiply by \(\frac{dA}{dt}\).
Differentiate \(K\) with respect to \(B\) and multiply by \(\frac{dB}{dt}\).
Sum the results from steps 1 and 2.
Step 1: Given Formula and Variables
We are given the formula:
\[ K = \frac{A^3 B^5}{10} \]
where both \( A \) and \( B \) are functions of \( t \).
Step 2: Apply the Product Rule
To find \(\frac{dK}{dt}\), we need to apply the product rule for differentiation. The product rule states:
\[ \frac{d}{dt}(uv) = u \frac{dv}{dt} + v \frac{du}{dt} \]
Here, \( u = A^3 \) and \( v = \frac{B^5}{10} \).
The correct answer is:
\[
\boxed{\frac{dK}{dt} = \frac{3A^2 B^5}{10} \frac{dA}{dt} + \frac{A^3 B^4}{2} \frac{dB}{dt}}
\]
This corresponds to option (A).