Ihave the following integral, (from 0-9) ∫1/9+x^2 dx (i know it has something to do with d/dx (tan^-1) but i don't know how to work around the number 9, ty

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?

For f(x) = 3x+1 and g(x) = x2 - 6, find (g/f)(x)

Which statement shows that 6.24 is a rational number? a. 6.24 = 6.242424 b. 6.24 = 6.24 c. 6.24 = 68⁄33 d. 6.24 = 66⁄25