Which pair of vectors could produce
a resultant of 357
a) 15 and 15
b). 20 and 20
c) 30 and 70
d) 20 and 60
e) 20 and 7070

The answer is    (d) 7/2======we have    we also  have an integral      notice how function f splits up at x = 0. there's a left piece and a right pieceso we'll need to do the same thing with our integral: split it at x = 0we use a property of integrals that allows us to split up and sum:     notice that for the piecewise function f, the function has the equationf(x) = x when x  ≤ 0. so for the integral  , f(x) = x so it changes into      for the piecewise function f, the function has the equationf(x) = x+1  when x  > 0. for the integral  , we have    therefore, back to our splitted integral:    

See diagram.we use washers to get the area and we will be integrating with respect to xouter radius is the  distance between y = e^x and y = -1    inner radius of washer is the distance between y = 1 and y = -1    the area of one cross-section of a washer is    solid lies between x = 0 and x = 2. the volume is    if you need this expanded, then    the question doesn't say to evaluate, so we're done.   

Ithink the answer is c hope i

This is called visual imagery. it is a memorization technique wherein an idea or a term is associated with an image, this in remembering ideas, especially as humans are very visual learners. this is also why visual aids a lot for memory retention.