Q. Given the function y=(−4+5x−3+7x−2)(−2−5x−1), find dxdy in any form.Answer: dxdy=
Identify Functions: We are given the function y=(−4+5x−3+7x−2)(−2−5x−1) and we need to find its derivative with respect to x. To do this, we will use the product rule, which states that the derivative of a product of two functions is the derivative of the first function times the second function plus the first function times the derivative of the second function.
Find Derivative of u: First, let's identify the two functions that are being multiplied. We have u=(−4+5x−3+7x−2) and v=(−2−5x−1). We will need to find the derivatives u′ and v′ separately.
Find Derivative of v: Let's find the derivative of u with respect to x. We have u=(−4+5x−3+7x−2). The derivative of a constant is 0, and the derivative of xn with respect to x is n⋅x(n−1). So, u′=dxd(−4)+dxd(5x−3)+dxd(7x−2)=0−15x−4−14x−3.
Apply Product Rule: Now, let's find the derivative of v with respect to x. We have v=(−2−5x−1). Again, the derivative of a constant is 0, and the derivative of xn with respect to x is n⋅x(n−1). So, v′=dxd(−2)−dxd(5x−1)=0+5x−2.
Simplify Expression: Now that we have u′ and v′, we can apply the product rule. The derivative of y with respect to x is given by dxdy=u′v+uv′. Substituting the derivatives we found, we get dxdy=(−15x−4−14x−3)(−2−5x−1)+(−4+5x−3+7x−2)(5x−2).
Distribute u′ with v: We need to simplify the expression for dxdy. First, let's distribute u′ with v: (−15x−4−14x−3)(−2)+(−15x−4−14x−3)(−5x−1). This simplifies to 30x−4+28x−3+75x−5+70x−4.
Distribute u with v′: Next, let's distribute u with v′: (−4)(5x−2)+(5x−3)(5x−2)+(7x−2)(5x−2). This simplifies to −20x−2+25x−5+35x−4.
Combine Like Terms: Now, we combine like terms to get the final expression for (dy)/(dx). We have 30x−4+28x−3+75x−5+70x−4−20x−2+25x−5+35x−4. Combining like terms, we get (dy)/(dx)=100x−4+28x−3+100x−5−20x−2.
Final Expression: Finally, we can write the derivative in a more simplified form by factoring out the common x term if desired. However, the expression 100x−4+28x−3+100x−5−20x−2 is already simplified and represents the derivative of the given function with respect to x.
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