Entering derivative formulas into WolframAlpha Pro

Questions
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This post was translated into English - please in future use only English language. ~ Moderation Team.

Hello Guys, I subscribed to wolfram alpha pro, and I would need help with the following question: How do I enter the derivative for the problems below into wolframalphapro? Determine the derivative of the following functions at the indicated points

a) f (x) = 3x + 2, at point 1.5
b) f (x) = 1 - 4x ², at point 0.1
c) f (x) = 2x ² - x - 1, at point 2.5

Entering function is quiet [simple?], but for example if I type the function f (x) = 3x + 2, without the information of the point, I believe, the system returns unexpected results. Thanks to whoever can help me?

2

With the help of google translate I got this

***"Hello Guys, I subscribed to wolfram alpha pro, and I would need help with the following question:
How do I enter the derivative for the problems below into wolframalphapro?

Determine the derivative of the following functions at the indicated points
a) f (x) = 3x + 2, at point 1.5
b) f (x) = 1 - 4x ², at point 0.1
c) f (x) = 2x ² - x - 1, at point 2.5

Entering function is quiet [simple?], but for example if I type the function f (x) = 3x + 2, without the information of the point, I believe, the system returns unexpected results. Thanks to whoever can help me?"***

I am not really sure whether you encounter problems without giving the point at which to evaluate the derivative or with the point. Here are the solutions for all examples:
http://www.wolframalpha.com/input/?i=+derivative+of+%283x%2B2%29+at+1.5
or

derivative of (3x+2) at 1.5

Here the same without the point:
http://www.wolframalpha.com/input/?i=+derivative+of+%283x%2B2%29+

derivative of (3x+2)

Here’s the second example
http://www.wolframalpha.com/input/?i=+derivative+of+%281±+4x%5E2%29+at+0.1+
and
http://www.wolframalpha.com/input/?i=+derivative+of+%281±+4x%5E2%29+

For the last example we get:
http://www.wolframalpha.com/input/?i=+derivative+of+%282x+²±+x±+1%29+at+2.5+
or
http://www.wolframalpha.com/input/?i=+derivative+of+%282x+²±+x±+1%29

All of these give the expected results, and also allow you to display the stepwise solutions.

Cheers,
M.

3

Hello Marco Thiel, Thanks for your answers helped and solved the problem.

Olá Marco Thiel, Obrigado pela sua respostas ajudou e resolveu o problema.

4

Marco - thank you very much for help with translation and the answer!

Flávio - in future please use only English language - this is a forum rule. Make use of automated translating services online if you do not know how to translate.