#1**+1 **

Solve for x over the real numbers:

cos(x) cosh(x) = 0

Split into two equations:

cos(x) = 0 or cosh(x) = 0

Take the inverse cosine of both sides:

x = π/2 + π n for n element Z

or cosh(x) = 0

cosh(x) = 0 has no solution since for all x element R, cosh(x)>=1 and True:

**Answer: | x = π/2 + π n for n element Z**

Guest Apr 15, 2017

#2**+1 **

coshx*cosx=0 x=?

\(cos\ x =0\\x=\frac{\pi}{2}+\pi\cdot n\\n \in ℤ\)

\(cosh\ x=\frac{1}{2}(e^x+e^{-x})>0\\ for \ x\in \Re\) **no solution**

**\(solution:\)**

\(coshx \cdot cosx=0\\x_1=\frac{\pi}{2} \\x_2=\frac{\pi}{2}+\pi\\x_3=-\frac{\pi}{2}\\x_4=-(\frac{\pi}{2}+\pi) \)

\(x=\frac{\pi}{2}+\pi\cdot n\) **Thank you! C.**

\( for\ n \in ℤ\)

!

asinus
Apr 16, 2017