Exponent Challenge

Algebra Level 1

2015 2015 2015 = ? \Large\dfrac{\color{#3D99F6}{2015}^{\color{#D61F06}{2015}}}{\color{#20A900}{2015}}=\ ?

2015 2014 { 2015 }^{ 2014 } 2014 2014 2015 2015 2014 2015 { 2014 }^{ 2015 }

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16 solutions

Azadali Jivani
Sep 16, 2015

By law of indices, we have a = a 1 a = a^1 , a 1 = 1 a a^{-1} = \dfrac1a , and a m n = a m ÷ a n a^{m-n} = a^m \div a^n . We have

201 5 2015 2015 = 201 5 2015 × 201 5 1 = 201 5 2014 . \Large \dfrac{2015^{2015}}{2015} = 2015^{2015} \times 2015^{-1} =\boxed{ 2015^{2014}}.

good way to do .i did it the same way :)

nadia nowshin - 5 years, 1 month ago
Tushar Kaushik
Sep 18, 2015

When bases are same under division powers get subtracted

Ernest Tee
Sep 18, 2015

But what is the exact answer? I got 10461721550869375

That is obviously not the exact answer since 201 5 2014 2015^{2014} should have 2014 × log 10 ( 2015 ) + 1 = 6655 \left\lfloor 2014\times \log_{10}(2015)\right\rfloor+1=6655 digits in base 10 (decimal) representation while the one you posted has only 17 17 digits.

The decimal representation of the answer isn't actually needed anyway. But if you want, you can get an approximation using logarithms and a decent scientific calculator.

A sufficient approximation that I got is 6.4558 × 1 0 6654 6.4558\times 10^{6654} .

Prasun Biswas - 5 years, 8 months ago
Gia Hoàng Phạm
Oct 20, 2018

201 5 2015 2015 = 201 5 2015 1 = 201 5 2014 \frac{2015^{2015}}{2015}=2015^{2015-1}=2015^{2014}

Venkatachalam J
May 11, 2016

Manisha Garg
Nov 22, 2015

We have: 2015^2015÷2015

= 2015 X 2015 X 2015 X........(2015 times)÷2015

Cancelling 2015 from numerator and denominator

= 2015 X 2015 X 2015 X .........(2014) times = 2015^2014

Shivangi Gupta
Oct 20, 2015

((2015)^2015)/2015=2015^2014

Lakshita Priya
Sep 25, 2015

In a fraction, if the numerator and the denominator are the same, then their powers get subtracted. As in this case, the number being 2015, it's powers are subtracted, i.e. 2015-1=2014.

Dev Jasuja
Sep 20, 2015

x^(x)/x=x^(x-1) Plug 2015 into the formula to obtain the solution.

Nouman K.J.
Sep 20, 2015

as bases are same, so it can be solved as 2015^(2015-1)=2015^2014

Hamza Muhammad
Sep 19, 2015

2015^2015 = 2015^2014 x 2015 :v then 2015 in numerator goes with 2015 in denominator So the result is 2015^2014 :v :D

Abdullah Al Moyen
Sep 18, 2015

2015^2015/2015=2015^(2015-1) = 2015^2014 (Ans)

Andrei Villanueva
Sep 18, 2015

We see 2015^2015/2015 that the exponent of the numerator is higher than the exponent of the denominator, so all we need to do is subtract the exponent of the numerator(2015) to the exponent of the denominator(1) sol= (2015) - (1) is equal to 2014, copy the base since their base is common. Therefore 2015^2015/2015 = 2015^2014

Mohammad Ahsan
Sep 18, 2015

We would just reduce a power from the numerator since the bases of the numerator and denominator are same

201 5 2015 2015 = 201 5 2014 × 2014 2014 = 201 5 2014 \frac{2015^{2015}}{2015}=\frac{2015^{2014}\times2014}{2014}=\boxed{2015^{2014}}

It's 2015/2015

Fernando Barrios Aguilar - 5 years, 8 months ago
Yosua Sibuea
Sep 16, 2015

For n= 1

1 1 1 = 1 \frac{1^{1}}{1} = 1

n=2 2 2 2 = 2 \frac{2^{2}}{2} = 2

n=3 3 3 3 = 3 \frac{3^{3}}{3} = 3

so, n n n = n 1 \frac{n^{n}}{n} = n-1

@David Amato Mantegari Hey, if you're not familiar with "how to write a problem in latex", then you can refer to Daniel's Latex Guide and keep post nice problems. Thanks!

Sandeep Bhardwaj - 5 years, 9 months ago

@Yosua Sibuea Hey, if you're not familiar with "how to write a problem/solution in latex", then you can refer to Daniel's Latex Guide .

Can you please elaborate on "how did you conclude "n^n=n^(n-1)" with the help of the values you chose for n"?

Sandeep Bhardwaj - 5 years, 9 months ago

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