Calculus AP need help!
posted by cynthia on .
1. f(x)=√5x+6, find f'(x)
2. f(x)=√4x^2+3x+4, find f'(x).
i got stuck.
f(x)=√5x+6=(5x+6)^1/2
f'(x)= 1/2(5x+6)^3/2*(5).

Almost. How did you get from ^1/2 to ^3/2? 1/2  1 = 1/2.
f = (5x+6)^(1/2)
use the power rule and chain rule:
f' = 1/2 * (5x+6)^(1/2) * 5 = 5/(2√(5x+6))
f = √(4x^2+3x+4)^(1/2)
f' = 1/2 * (4x^2+3x+4)^1/2) * (8x+3) = (8x+3)/(2√(4x^2+3x+4)) 
oops.. i thought 1/2 to 3/2. now i understand. thanks