How do you determine the area to the left of #g(y)=3-y^2# and to the right of #x=-1#?

1 Answer
Mar 27, 2015

Determine the area to the left of #g(y)=3-y^2# and to the right of #x=-1#

Turn your thinking #90^@#.

This is the dual problem of the problem: Find the area under #f(x)=3-x^2# and above #y=-1#.

in terms of #y# "left" = in terms of #x# "under"

in terms of #y# "right" = in terms of #x# "above"

You don't need to change the problem if you can change your thinking. Usually (initially) we found the area between two functions ox #x# by integrating #int# (the top function - the bottom function) #dx#

This time we'll do:

#int# (right function - left function) #dy#

Limits of integration are the values of #y# at the points of intersection. Namely: solve the system: #x=3-y^2# and #x=-1#.

#3-y^2--1# at #y=+-2#

So now we know to evaluate:

#int_-2^2((3-y^2-(-1)) dy int_-2^2(4-y^2)dy# which I think you can finish.