Calculus Test Prep - Answers + Explanations

  • Context: Undergrad 
  • Thread starter Thread starter hodeez
  • Start date Start date
  • Tags Tags
    Calculus Review
Click For Summary

Discussion Overview

The discussion revolves around preparation for a calculus test, focusing on specific problems from a review sheet. Participants seek answers and explanations for various calculus concepts, including derivatives and graphing functions.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents a derivative for a function involving a product rule and seeks feedback on their calculation.
  • Another participant discusses the logarithmic function and mentions using a TI89 calculator to graph and find derivatives.
  • A query is raised about proving whether the derivative of a function is constantly positive or negative, leading to a discussion about the minimum value of the cosine function.
  • Participants explore the implications of the minimum value of cosine on the derivative of a related function.
  • One participant describes a parametric equation and seeks confirmation on their approach to finding a zero of the function.
  • A participant expresses confusion over a derivative calculation and notes a discrepancy between their answer and the calculator's output.
  • Another participant provides a derivative expression for a function involving sine and seeks clarification on their earlier mistake.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and confusion regarding specific calculus problems, with no clear consensus on the correctness of the answers provided. Disagreements arise particularly around the interpretation of derivative calculations and the properties of trigonometric functions.

Contextual Notes

Some discussions involve assumptions about the behavior of trigonometric functions and the use of calculators, which may not be universally applicable. There are also unresolved steps in the mathematical reasoning presented.

hodeez
Messages
28
Reaction score
0
Hi guys, I have a calculus test tomorrow and it'll be great if I can receive some answers + explanations! my review sheet is attached. if this is breaking the rules I am sorry.

hope this actually helps some other people too
 

Attachments

Last edited:
Physics news on Phys.org
for #1
i got 3x^2-sin(xy^2)*2xy [dy/dx]*y^2
whadaya thinks?
 
for #2) its log(x)/log4 b)then graph it with my TI89 then find the deriv @ .4


at work right now so no calculator on me =)
btw: does the TI89 have a test function == like the ti86?
 
#3) f'(x)=2+cosx so we have to prove f'(x) is constantly positive or negative.. but how would we approach that?
 
Originally posted by hodeez
#3) f'(x)=2+cosx so we have to prove f'(x) is constantly positive or negative.. but how would we approach that?

What's the minimum of cos(x) (assuming x is real)
 
Originally posted by NateTG
What's the minimum of cos(x) (assuming x is real)

sorry I am not quite following you. on the y-axis it is -1, and on the x it can be -infinite. please correct me if I am wrong
 
So, if the minimum value of cos(x) is -1, what is the minimum value of 2+cos(x)?
 
lol wow i feel so dumb

thanks onward to the next question after i finish some quick job for my boss.
 
i got x-4=y^3+y
so turn my ti89 to parametric mode and y1 = t^3+t
y2= -1 right? (since its g(3) 3-4 = -1)
then i trace for a zero?
 
Last edited:
  • #10
just came back from my test and i got confused on a question... find the deriv of x+sin(xy) i got (-sec(x)-y)/x but the calc gave me 1

thanks to all the people that replied and (attempted to) help
 
  • #11
d/dx{x+sin(xy)} = 1 +cos(xy)[xdy/dx+y]
 
  • #12
oh my goddd what did i do? i messed up.. oh wells :smile:
thanks himanshu121 for reminding me of my errror
 

Similar threads

Replies
5
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 25 ·
Replies
25
Views
5K