Find y′ if y=x2+12x−3.
Solution The function y is the quotient of f(x)=x2+1 and g(x)=2x−3. Using the Quotient Rule, we have y′=ddx(x2+12x−3)=[ddx(x2+1)](2x−3)−(x2+1)[ddx(2x−3)](2x−3)2=(2x)(2x−3)−(x2+1)(2)(2x−3)2=4x2−6x−2x2−2(2x−3)2=2x2−6x−2(2x−3)2
provided x≠32.