Recall that the general Cauchy problem (or IVP) for the wave equation on $\mathbb{R}$ is
$$u_{t\, t}=c^2u_{x\, x},u(x,0)=f(x),\text{ and }\,u_t(x,0)=g(x)\text{ for }x\in \mathbb{R}.$$
This can be solved using d'Alembert's formula:
$$u(x,t)=\frac{1}{2}(f(x+c t)+f(x-c t))+\frac{1}{2c}\int _{x-c t}^{x+c t}g(s)ds.$$
Apply d'Alembert's formula to solve the wave problem
$$u_{t\, t}=c^2u_{x\, x},u(x,0)=e^{-x^2}\cos(10x),\text{ and }\,u_t(x,0)=e^{-x^2}\sin(10x)\text{ for }x\in \mathbb{R}.$$