Melody

logan:

if AC=BC=4, what is AB

joyopoo:

how do you find the area of a trapezoid

Quote:

Ben the hiker wants to spend the night on top of a mountain. He hikes all day long towards the top and camps there overnight. The following day he is taking the same path down towards the bottom when he suddenly looks at his watch en notices that he is at the very same spot at the very same time of the day as the day before on his way up. 'What a coïncidence!' he exclaims!
Give an estimate of the probabilty that a hiker will be at exactly the same spot on the mountain at the same time of the day on his return trip as he was the previous day's hike up the mountain and explain why.

Stu:

1. Differentiate (use appropiate notation)
a) y = x⁹
y'=9x⁸

b) f(x)=5x³ - 3x + 6
f'(x)=15x² -3

c) y = 4x^-5
y'=20x⁴ (You could have used dy/dx= but y' is fine as well - But it should have been y' = -20x^-5-1 = ?) Can you finish this please Stu

2. d/dx (-12x)
f"(x) = -12 Not f"(x) You only use " when you differentiate twice.
The best answer would be d/dx (-12x) = -12

3. differentiate
a) y = (2x+3)⁴
y' = 4*(2x+3)³*2 That is correct but you can simplify this answer.

b) f(x) = x² ( 2x+3)⁴
f'= 2x+4*(2x+3)³*2

b) f(x) = x² ( 2x+3)⁴
For this question you need to use the product rule. If y=uv then y'=uv' + vu'
u=x² so u'=2x
v=(2x+3)⁴ so v'=4(2x+3)³*2 = 8(2x+3)³
Now you have to substitute those values into the formula and simplify the answer.
Could you try doing that please Stu?

Thanks,
Melody.

ehhthing:

Does (-9) x 1/4 + (-1/2) = 11/4 or what?

Guest:

find the midpoint of the line segment with the given endpoints. (3,5) (-5,-5)