Solve 22 and 24 number.it is simple differentiation but tell me what is mean by f(x) and g(x) here and how solve it.i am very worried.?

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3 Answers
Aug 16, 2017

See explanation.

Explanation:

Questions 22 and 24 are the basic properties of derivatives.

22 says that the derivative of a difference of 2 functions is the difference of the functions' derivatives

24 says that the derivative of a sum of 3 functions is the sum of the functions' derivatives.

In these questions #f(x)#, #g(x)# and #h(x)# are any functions whose derivative is defined

Aug 16, 2017

Please see below.

Explanation:

I think that you are asking about the notation #f(x)#.

We use this notation for a function.

One way to think about a function is simply as another name for #y#.

So instead of writing

#y = x^2+3#

We can write

#f(x) = x^2+3#
We read this "f of x equals x squared plus 3".
#f# is the name of the function and #f(x)# is a name for #y#.

Instead of writing:

If #y = x^2+3#, find #y# when #x = 2#

We can write

If #f(x) = x^2+3#, find #f(3)#
We read #f(3)# as "f of 3# and, since #(3)^2+3 = 9#, we say "f of 3 is [or equals] 9".

A function is like an operation performed on some input. It takes an input and gives an output. Some of the algebra operations and some calculator buttons are (simple) functions.

With #y = f(x)# we write #f'(x)# (read "f prime of x") for #dy/dx#

Instead of saying

Find #dy/dx# when #x = 5#

we can say

Find #f'(5)# ("find f prime of 5")

You can read more about functions at Socratic under the Subject: Algebra.
Use the Subject pull-down list above. Select Algebra.
Then when Algebra loads, select Topics. You can look for topics about functions.

On a personal note

Many students are now taught about functions when they learn algebra. The first time I saw a function or the word "function" was in my first calculus class.
For a long time I thought of functions as I have described them. #f(x) is another name for #y#.
There's more to it than that, but it gets you going in the right direction.

Aug 16, 2017

Question 22 could be rewritten as follows.

With #y = f(x)# and #z = g(x)#

what is #d/dx(y-z)#?

Answer (C.) #f'(x)-g'(x)# is the same as #dy/dx-(dz)/dx#