How do you solve #16^x = x^2# ?

2 Answers
Nov 26, 2015

Took it up to a point beyond which I did not know how to mathematically resolve.

Explanation:

Given: #16^x =x^2#

To get rid of the #x# on the right side take logs to base #x#

#xlog_x(16)=2#

#log_x(16)=2/x#

#=> x^(2/x)=16#

#=> (x^(1/x))^2 =4^2#

#=> x^(1/x)=4#
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You could do:

#1/x ln(x)=ln(4)#

But I have idea where this would take you!

Nov 26, 2015

#x = -1/2#

Explanation:

The graph of #16^x# intersects the graph of #x^2# once, at #(-1/2, 1/4)#

#16^(-1/2) = 1/sqrt(16) = 1/4 = (-1/2)^2#

graph{(y-x^2)(y-16^x) = 0 [-5.313, 4.687, -0.7, 4.3]}