Assume that x is a char variable that has been declared and already given a value. Write an expression whose value is true if and only if x is a decimal digit (0-9).

Least square fit to polynomial write a function leastsquarefit3pol that solves a linear system of equations to find a least squares fit of a third order polynomial to an experimental data set given as two row arrays. the function leastsquarefit3pol must explicitly solve a set of linear equations and cannot use polyfit. there should be no restriction on the size of the problem that can be solved.

What is one reason why indoor air pollution has become an increasing problem.

Which of the following is an example of synchronous communication? a) e-mail b) voicemail c) telephone conversation d) text message.