## joycelefebvre 3 years ago find slope of tangent line y=f(x)=xsquared + 1 at (2,5) given f'(x)=2x

1. cwrw238

the slope = 2x at (2,5) x = 2 so slope of tangent = 2(2) = 4

2. 2bornot2b

So your question is to find the slope of the equation$$f(x)=x^2+1$$ at (2,5) given f'(x)=2x

3. 2bornot2b

joycelefebvre are you new to OS?

4. joycelefebvre

yes could you show me your work on that please i'm studying for praxis 0061 my study guied doesnt show work its horrible tu

5. 2bornot2b

6. 2bornot2b

Given any function, the derivative of the function is the equation to the slope of the given equation--------did you know that?

7. joycelefebvre

kinda I took calc in college in 93 and its not coming back

8. 2bornot2b

OK, then I am trying to refresh that. Suppose you have a function y=f(x), so the function y=f'(x) is the equation of the tangent of the function y=f(x)

9. 2bornot2b

OK?

10. 2bornot2b

So your given function is $$f(x)=x^2+1$$ and $$f'(x)=2x$$

11. 2bornot2b

Now as I told you earlier, $$f'(x)$$ should be the equation of the tangent at any point

12. 2bornot2b

Your question asks you to find the equation of the tangent at (2,5) so just put x=2 in the equation to tangent i.e. 2x2=4. So the answer is 4 Got it?

13. joycelefebvre

omg I was trying to do y2-y1/x2-x1

14. 2bornot2b

This is actually a theorem.. If you just remember it you don't have to find the tangent that way.......... I mean the way you are trying using the formula $$\frac {y2-y1}{x2-x1}$$

15. 2bornot2b

The theorem is, Let y=f(x) be a given equation, to find the equation to the tangent at any point is y=f'(x) where f'(x) is the derivative of the function f(x)

16. 2bornot2b

Is that clear, any problem?

17. joycelefebvre

tu i couldn't find the praxis study guied for 0061 so i got the cliff notes and its all text no examples

18. 2bornot2b

Did you know you can chat with other users in the maths group?

19. 2bornot2b

In that way you can get help from experts?

20. 2bornot2b

Come join me in the chat room (do you know how?)

21. joycelefebvre

no

22. 2bornot2b

Do you see those green boxes below

23. joycelefebvre

24. 2bornot2b

See there I have posted you a chat message

25. 2bornot2b

Yes, I am 31, thats my level.

26. 2bornot2b

But chatting is a different thing

27. joycelefebvre

my lap top keeps telling me i cant run this script

28. 2bornot2b

OH, I see, what operating system are you using?