How do you find the equation of the tangent line to the graph y=5^(x-2)y=5x2 through point (2,1)?

1 Answer
Dec 13, 2016

Find the derivative of the function.

y= 5^(x- 2)y=5x2

lny = ln(5^(x- 2))lny=ln(5x2)

lny = (x- 2)ln5lny=(x2)ln5

1/y(dy/dx) = 1(ln5) + (x- 2)01y(dydx)=1(ln5)+(x2)0

1/y(dy/dx) = ln51y(dydx)=ln5

dy/dx = ln5/(1/y)dydx=ln51y

dy/dx= ln5(5^(x - 2))dydx=ln5(5x2)

The slope of the tangent is therefore ln5(5^(2- 2)) = ln5ln5(522)=ln5.

y -y_1 = m(x- x_1)yy1=m(xx1)

y - 1 = ln5(x- 2)y1=ln5(x2)

y - 1= ln5x - 2ln5y1=ln5x2ln5

y = ln5x - 2ln5 + 1y=ln5x2ln5+1

Hopefully this helps!