Solving derivative- possible without quotient rule?

In summary, the problem is to find the derivative of a complicated function at a specific value without using the quotient rule. The solution involves splitting the function into three parts and using the product rule, as well as using trigonometric identities to simplify the expression. Clarification of notation is also recommended for clearer understanding.
  • #1
Persimmon
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Homework Statement


find the following derivative
d/dx [g(x + 1)(√(2+ (x + 8)^(1/3))/(cos(tan(sin(tan(sin x))))]
at x = 0

Homework Equations





The Attempt at a Solution



I split the big long derivative into 3 functions:
a(x) = g(x + 1)
b(x) = √(2+ (x + 8)^(1/3))
c(x) = cos(tan(sin(tan(sin x))))

and got : (a'x*bx + b'x*ax)(cx)-c'x*px*qx)/cx^2
subbing in x = 0 that simplified into 2*g'(1)
but it was mentioned that it's possible to solve this without the quotient rule. I can't figure out how you would solve this derivative if you didn't use the quotient rule.
 
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  • #2
Persimmon said:

Homework Statement


find the following derivative
d/dx [g(x + 1)(√(2+ (x + 8)^(1/3))/(cos(tan(sin(tan(sin x))))]
at x = 0

Homework Equations





The Attempt at a Solution



I split the big long derivative into 3 functions:
a(x) = g(x + 1)
b(x) = √(2+ (x + 8)^(1/3))
c(x) = cos(tan(sin(tan(sin x))))

and got : (a'x*bx + b'x*ax)(cx)-c'x*px*qx)/cx^2
subbing in x = 0 that simplified into 2*g'(1)
but it was mentioned that it's possible to solve this without the quotient rule. I can't figure out how you would solve this derivative if you didn't use the quotient rule.
Instead of dividing by cos(...), you can multiply by sec(...). That way you're set up to use the product rule.

BTW, your notation is not very helpful.
a'x*bx + b'x*ax)(cx)-c'x*px*qx)/cx^2
As written this looks like a' * x * b * x etc. To be clearer, write a'(x) * b(x) etc.
 
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  • #3
Sorry for the unclear notation. I was trying to make it clearer so there wouldn't be endless brackets but I guess it's even more confusing that way. Thank you for your help!
 

1. What is the quotient rule and why is it used in solving derivatives?

The quotient rule is a mathematical rule used to find the derivative of a function that is a ratio of two other functions. It is used when the derivative of a function cannot be found by using the basic rules of differentiation.

2. Is it possible to solve derivatives without using the quotient rule?

Yes, it is possible to solve derivatives without using the quotient rule. There are other rules and techniques, such as the product rule, chain rule, and power rule, that can be used to find the derivative of a function.

3. When should I use the quotient rule in solving derivatives?

The quotient rule should be used when the function being differentiated is a quotient of two other functions. It is also helpful to use when the other rules of differentiation cannot be applied.

4. Can the quotient rule be simplified or rewritten?

Yes, the quotient rule can be rewritten in different forms depending on the specific function being differentiated. For example, it can be written as a single fraction or as a product of two fractions.

5. What are the common mistakes to avoid when using the quotient rule?

Common mistakes when using the quotient rule include incorrectly differentiating the numerator and denominator separately, forgetting to use the negative sign in the formula, and not simplifying the final answer. It is important to carefully apply the rule and double check the solution for accuracy.

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