Saturday

September 20, 2014

September 20, 2014

Posted by **Ifi** on Sunday, October 28, 2012 at 4:13am.

My ans is (8,48). First i do f'x then i find x and lastly i find y. I do this because the max/min point is the point where tangent line pass through. Pls correct me if im wrong.

- Math -
**Steve**, Sunday, October 28, 2012 at 6:04amNo, (8,48) is the max, so the tangent there is horizontal. It will not pass through the origin.

f'(x) = -2x+16

you want to find (h,k) where the line joining (0,0) and (h,k) has slope -2h+16

k/h = -2h+16

But, k = -h^2+16h-16, so

-h^2+16h-16 = h(-2h+16)

-h^2 + 16h - 16 = -2h^2 + 16h

h^2 - 16 = 0

h = 4,-4, so k = 32,-96

The points are thus (-4,-96) and (4,32)

Check:

f'(4) = 8 = 32/4

f'(-4) = 24 = 96/4

**Answer this Question**

**Related Questions**

Calculus - Sketch a graph of the parabola y=x^2+3. On the same graph, plot the ...

Math - If f(x)=3x^2-5x, find the f'(2) & use it to find an equation of tangent ...

math - A(-3,-2) B(8,4)are the ends of the diameter of a circle. the tangent of ...

math - A(-3,-2) B(8,4)are the ends of the diameter of a circle. the tangent of ...

math - A(-3,-2) B(8,4)are the ends of the diameter of a circle. the tangent of ...

math - A(-3,-2) B(8,4)are the ends of the diameter of a circle. the tangent of ...

math - A(-3,-2) B(8,4)are the ends of the diameter of a circle. the tangent of ...

math - A(-3,-2) B(8,4)are the ends of the diameter of a circle. the tangent of ...

math - A(-3,-2) B(8,4)are the ends of the diameter of a circle. the tangent of ...

math - A(-3,-2) B(8,4)are the ends of the diameter of a circle. the tangent of ...