Test:23 QNo:10

Find dy/dx at x=1, y=e(x)x

8 Answers

1
Manmay kumar Mohanty ·

I'M GETTING '2e'. But given 'e'. please help.

1
Ajaay Srinivasan ·

e+1 ????????

39
Pritish Chakraborty ·

y = e^{x^{x}} => logy = xlog(e^{x}) => \frac{1}{y} \frac{dy}{dx} = log(e^{x}) + \frac{x}{e^{x}}.e^{x} = log(e^{x}) + x

=> \frac{dy}{dx} = e^{x^{x}}(log(e^{x}) + x)

At x = 1,

e^{1^{1}}(log(e^{1}) + 1) = e(1+1) = 2e

where log is the natural log, hence log(e) = 1.
Manmay is correct if my calculations are correct!

1
Manmay kumar Mohanty ·

definitely the options didn't have 2e.

i got the ans as 2e but given was e so i had to leave it.

1
Anirudh Kumar ·

pritish bhaiya above should be wrong .
becuase when we use \log m^{n} = n\log m
you have to take out power on m. but you have taken the power on n. a mistake there

so . sloution would be like this
\ln y= x^{x}\ln e = x^{x
let\: z= x^{x}=> \ln z = x\ln x
=> z^{'}= x^{x}(\ln x+1)
=> y^{'}= y(z^{'})=y[x^{x}(\ln x+1)]

thus \: at \: x=1 \: y^{'}=e

39
Pritish Chakraborty ·

oooo! I didn't notice..
yes then it's e..thanks for correcting me!

1
Tapas Gandhi ·

29
govind ·

Ya Pritish u have made a mistake while taking out the powers...coz 233 is not equal to (23)3..so the final answer will be e...

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