Question

Find y'' if y=14x(sin(x))

Answer 1

Tangent line equation is y-b=m(x-a) 
Based on the problem a=π/2, b=7π 

Find m using derivatives of y=14x sinx 
y'(x) =14(sin x) + 14x (cos x) 
m=y'(π/2)=14(1)+14π/2(0)=14 

Therefore the equation is 
y - 7π = 14(x - π/2) 
y - 7π = 14x - 7π 
y = 14x

Answer 2

Tangent line equation is y-b =m(x-a) Based on the problem a=π/2, b=7π.