How do you solve #2^(x) - 2^(-x) = 5#?
2 Answers
Explanation:
Since
#2^x-1/2^x=5#
Multiply each term by
#2^x(2^x)-1/2^x(2^x)=5(2^x)#
To simplify
#2^(x+x)-1=5(2^x)#
#2^(2x)-5(2^x)-1=0#
Let
#u^2-5u-1=0#
Use the quadratic formula to show that
#u=(-(-5)+-sqrt(5^2-(4*-1*1)))/(2*1)=(5+-sqrt29)/2#
Recall that
#2^x=(5+sqrt29)/2#
#x=log_2((5+sqrt29)/2)#
Using
#x=log_2(5+sqrt29)-log_2(2)#
#x=log_2(5+sqrt29)-1#
As for the negative version of
#2^x=(5-sqrt29)/2#
Has no solutions since
Explanation:
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