Q. Given that x=w5+5, find dwd(3x2+3cosw) in terms of only w.Answer:
Express x in terms of w: First, we need to express x in terms of w to be able to differentiate the function with respect to w. We are given that x=w5+5. We will use this to differentiate the function 3x2+3cos(w) with respect to w.
Apply chain rule: Next, we need to apply the chain rule to differentiate 3x2 with respect to w. The chain rule states that the derivative of a composite function is the derivative of the outer function evaluated at the inner function times the derivative of the inner function. In this case, the outer function is 3u2 (where u=x) and the inner function is x=w5+5.
Derivative of x with respect to w: The derivative of 3u2 with respect to u is 6u. So, the derivative of 3x2 with respect to x is 6x. Now we need to multiply this by the derivative of x with respect to w, which is the derivative of w0 with respect to w.
Multiply derivatives: The derivative of w5 with respect to w is 5w4, and the derivative of a constant (5) is 0. Therefore, the derivative of x with respect to w is 5w4.
Substitute x into expression: Now we can multiply the derivative of 3x2 with respect to x by the derivative of x with respect to w to get the derivative of 3x2 with respect to w. This gives us 6x×5w4.
Differentiate 3cos(w): Substituting x=w5+5 into 6x⋅5w4, we get 6(w5+5)⋅5w4. This simplifies to 30w4(w5+5).
Combine derivatives: Now we need to differentiate 3cos(w) with respect to w. The derivative of cos(w) with respect to w is −sin(w). Therefore, the derivative of 3cos(w) with respect to w is −3sin(w).
Combine derivatives: Now we need to differentiate 3cos(w) with respect to w. The derivative of cos(w) with respect to w is −sin(w). Therefore, the derivative of 3cos(w) with respect to w is −3sin(w).Finally, we add the derivatives of 3x2 and 3cos(w) with respect to w to get the derivative of the entire function with respect to w. This gives us w2.
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