Use the alternative curvature formula K=|a x v|/|v|^3 to find the curvature of the following parameterized curves.
r(t)= (4+t^2,t)

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

The length of triangle base is 26. a line, which is parallel to the base divides the triangle into two equal area parts. find the length of the segment between triangle legs.

Lance lived in portugal and brazil for a total of 14 months to learn portuguese. he learned an average of 130 new words per month when he lived in portugal, and an average of 150 new words per month when he lived in brazil. in total he learned 1920 new words. write a system of equations to represent the situation. use x to represent portugal, and y to represent brazil