Who was the first person to make a portable computer?

For her science class, elaine is creating a presentation on weather in the united states. she wants to make the presentation beautiful and interesting by drawing simple cloud or wave shapes. which is the best way for elaine to draw these shapes?

Donnie does not have powerpoint. which method would be best for elana to save and share her presentation as is? a pdf a doc an rtf a ppt

For positive constants a and b, the force between two atoms in a molecule is given f(r) = −a r2 + b r3 , where r > 0 is the distance between the atoms. note: a and b are upper case letters. (a) find f '(r) = (b) find the critical point for f(r). r = (c) find f ''(r) = (d) find the value of r so that f ''(r) = 0.