1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Amiraneli [1.4K]
2 years ago
6

(d). Use an appropriate technique to find the derivative of the following functions:

Mathematics
1 answer:
natima [27]2 years ago
3 0

(i) I would first suggest writing this function as a product of the functions,

\displaystyle y = fgh = (4+3x^2)^{1/2} (x^2+1)^{-1/3} \pi^x

then apply the product rule. Hopefully it's clear which function each of f, g, and h refer to.

We then have, using the power and chain rules,

\displaystyle \frac{df}{dx} = \frac12 (4+3x^2)^{-1/2} \cdot 6x = \frac{3x}{(4+3x^2)^{1/2}}

\displaystyle \frac{dg}{dx} = -\frac13 (x^2+1)^{-4/3} \cdot 2x = -\frac{2x}{3(x^2+1)^{4/3}}

For the third function, we first rewrite in terms of the logarithmic and the exponential functions,

h = \pi^x = e^{\ln(\pi^x)} = e^{\ln(\pi)x}

Then by the chain rule,

\displaystyle \frac{dh}{dx} = e^{\ln(\pi)x} \cdot \ln(\pi) = \ln(\pi) \pi^x

By the product rule, we have

\displaystyle \frac{dy}{dx} = \frac{df}{dx}gh + f\frac{dg}{dx}h + fg\frac{dh}{dx}

\displaystyle \frac{dy}{dx} = \frac{3x}{(4+3x^2)^{1/2}} (x^2+1)^{-1/3} \pi^x - (4+3x^2)^{1/2} \frac{2x}{3(x^2+1)^{4/3}} \pi^x + (4+3x^2)^{1/2} (x^2+1)^{-1/3} \ln(\pi) \pi^x

\displaystyle \frac{dy}{dx} = \frac{3x}{(4+3x^2)^{1/2}} \frac{1}{(x^2+1)^{1/3}} \pi^x - (4+3x^2)^{1/2} \frac{2x}{3(x^2+1)^{4/3}} \pi^x + (4+3x^2)^{1/2} \frac{1}{ (x^2+1)^{1/3}} \ln(\pi) \pi^x

\displaystyle \frac{dy}{dx} = \boxed{\frac{\pi^x}{(4+3x^2)^{1/2} (x^2+1)^{1/3}} \left( 3x - \frac{2x(4+3x^2)}{3(x^2+1)} + (4+3x^2)\ln(\pi)\right)}

You could simplify this further if you like.

In Mathematica, you can confirm this by running

D[(4+3x^2)^(1/2) (x^2+1)^(-1/3) Pi^x, x]

The immediate result likely won't match up with what we found earlier, so you could try getting a result that more closely resembles it by following up with Simplify or FullSimplify, as in

FullSimplify[%]

(% refers to the last output)

If it still doesn't match, you can try running

Reduce[<our result> == %, {}]

and if our answer is indeed correct, this will return True. (I don't have access to M at the moment, so I can't check for myself.)

(ii) Given

\displaystyle \frac{xy^3}{1+\sec(y)} = e^{xy}

differentiating both sides with respect to x by the quotient and chain rules, taking y = y(x), gives

\displaystyle \frac{(1+\sec(y))\left(y^3+3xy^2 \frac{dy}{dx}\right) - xy^3\sec(y)\tan(y) \frac{dy}{dx}}{(1+\sec(y))^2} = e^{xy} \left(y + x\frac{dy}{dx}\right)

\displaystyle \frac{y^3(1+\sec(y)) + 3xy^2(1+\sec(y)) \frac{dy}{dx} - xy^3\sec(y)\tan(y) \frac{dy}{dx}}{(1+\sec(y))^2} = ye^{xy} + xe^{xy}\frac{dy}{dx}

\displaystyle \frac{y^3}{1+\sec(y)} + \frac{3xy^2}{1+\sec(y)} \frac{dy}{dx} - \frac{xy^3\sec(y)\tan(y)}{(1+\sec(y))^2} \frac{dy}{dx} = ye^{xy} + xe^{xy}\frac{dy}{dx}

\displaystyle \left(\frac{3xy^2}{1+\sec(y)} - \frac{xy^3\sec(y)\tan(y)}{(1+\sec(y))^2} - xe^{xy}\right) \frac{dy}{dx}= ye^{xy} - \frac{y^3}{1+\sec(y)}

\displaystyle \frac{dy}{dx}= \frac{ye^{xy} - \frac{y^3}{1+\sec(y)}}{\frac{3xy^2}{1+\sec(y)} - \frac{xy^3\sec(y)\tan(y)}{(1+\sec(y))^2} - xe^{xy}}

which could be simplified further if you wish.

In M, off the top of my head I would suggest verifying this solution by

Solve[D[x*y[x]^3/(1 + Sec[y[x]]) == E^(x*y[x]), x], y'[x]]

but I'm not entirely sure that will work. If you're using version 12 or older (you can check by running $Version), you can use a ResourceFunction,

ResourceFunction["ImplicitD"][<our equation>, x]

but I'm not completely confident that I have the right syntax, so you might want to consult the documentation.

You might be interested in
Two square are congruent ,if they have same ______​
OverLord2011 [107]

Two squares are congruent if they have the same side length.

3 0
3 years ago
Read 2 more answers
You are a financial advisor whose client is concerned about losing his investment if a company goes out of business. Which of th
34kurt

Answer:

You should advise him to buy preferred stock.

Step-by-step explanation:


7 0
3 years ago
Read 2 more answers
Biology if one honeybee makes 1/12 teaspoons of honey during its life time how many homey bees do you need to make1/2 tea spoons
Korolek [52]

Answer:

(1/2) / (1/12)

(1/2) * (12/1) = 12/2 = 6


6 0
3 years ago
Find the volume of the cone
son4ous [18]
The volume is 800pi cubic feet

3 0
3 years ago
What is an equivalent expression for 2x + 10x and 2(x-4) + x
tester [92]
2x+10x combine like terms
12x
2(x-4)+4 Distribute 2
2x-8+4
combine like terms
2x-4
6 0
3 years ago
Other questions:
  • If sin theta = 5/6, what are the values of cos theta and tan theta?
    14·1 answer
  • Second problem please help cause i don’t have a clue !
    9·1 answer
  • What is the value of x in the following system of equations? 11x + 12y = 13 14x + 15y = 16 A. x = −2 B. x = −1 C. x = 1 D. x = 2
    14·1 answer
  • Can someone help me with 1-4
    12·1 answer
  • Tim is painting his storage shed who buys 4 gallons of white paint and 3 gallons of blue paint meaning of each gallon of white p
    9·2 answers
  • 1. Place a _____________ on the number line for the number in the expression.
    11·1 answer
  • Use the two points and the line to find the y-intercept
    7·1 answer
  • A sample of customers from Barnsboro National Bank shows an average account balance of $315 with a standard deviation of $87.A s
    13·1 answer
  • If there are 5380 feet in a mile Express 4000 get In kilometers<br><br>please show how you go it​
    11·1 answer
  • Susan sells cookies. She was gifted all of her supplies. Susan uses the function p(x) = 2x to represent her profit after selling
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!