Friday

September 19, 2014

September 19, 2014

Posted by **Tiffany** on Sunday, April 7, 2013 at 11:47pm.

e^x + e^-x = 6

- exponential equation -
**Reiny**, Monday, April 8, 2013 at 12:00amlet e^x = a

then we have

a + 1/a = 6

a^2 + 1 - 6a = 0

a^2 - 6a = -1

completing the square, (in this case faster than using the formula)

a^2 - 6a + 9 = -1 + 9

(a-3)^2 = 8

a-3 = ± √8

a = 3± 2√2

so e^x = 3 + √8 OR e^x = 3 - √8

using my calculator

x = ln(3+√8) = 1.7627.. or

x = ln(3-√8) = -1.7627..

**Answer this Question**

**Related Questions**

exponential equation-Algebra - Solve the exponential equation. Express the ...

Math - Exponential equation - Solve the exponential equation. Express your ...

Algebra Help - Let x = log_2 1/8 Write the exponential form of the equation and ...

Algebra-please check my answers - Solve the equation by expressing each side as ...

MATH - State whether each equation in Exercises 25–30 represents a linear, ...

Math - State whether the equation y=10^3x represents a linear, quadratic, or ...

Math - State whether the equation y=10^3x represents a linear, quadratic, or ...

Algebra - Let x = log_2 1/8 Write the exponential form of the equation and solve...

Algebra - Write the exponential form of the equation and solve the equation for ...

Pre calculus - Okay, I'm really fuzzy about my log and exponential chapter. For...