SOLUTION: For what positive integer value will 2^x first exceed 3x+2

Algebra.Com
Question 1062025: For what positive integer value will 2^x first exceed 3x+2
Answer by math_helper(2461)   (Show Source): You can put this solution on YOUR website!
increases rapidly for increasing positive x
also increases for increasing positive x

I would use trial-and-error, especially since the problem asks for an integer value of x


x=2 —> and
x=6 —> and
so the answer lies between 2 and 6… plug in the remaining values of x (3,4,5) and you will find it.

Here there are only three additional values to check. If however you ever find you have many more values to check (say you are using trial and error and you know "x=1" is too low while "x=100" is too high) then you can use a binary search: x=1 too low, x=100 too high, x=50 would be your next guess. If that were too high you'd use x=25 next, if x=50 were too low, you'd use x=75 as your next guess, etc. You will converge on the answer pretty quickly.

Another approach to problems like this would be to take the log( ) of both sides of your equation and isolate the log()'s on one side of the equation (even if 'x' appears on both sides). The reason is the side with the log() functions is likely to grow much more slowly than the other side of the equation so as you guess values, one side changes quickly, the other side stays close to the same value.


RELATED QUESTIONS

For what positive integer would 2\left(3\right)^{^x} exceed 50x +... (answered by Alan3354)
[ if x is a positive integer, what is the least value of x^2-2x+3?... (answered by TimothyLamb)
What is the sum of all integral values of x for which 18(x^2-7x+10)/(x^3-6x^2+3x+10) is (answered by ikleyn,Edwin McCravy)
{{{ y = 6x^2 + bx + 11 }}} What is the smallest positive integer for b that will force... (answered by Edwin McCravy)
For what value of x is x2-3x-18... (answered by unlockmath)
At what value of x does 4x eventually exceed 7x2 + 8x +... (answered by Alan3354,solver91311)
At what value of x does 4x eventually exceed 7x2 + 8x +... (answered by josgarithmetic)
Given 60=2^2 x 3 x 5 and 1050=2 x 3x 5^2 x 7, find (a) the smallest integer m such... (answered by richard1234)
If A=3x+100 and B=4x+20, for what value of x does A exceed B by 652. (answered by jim_thompson5910)