x/y + 3z^2 for x= 2/3, y= 6/7, and z=3
=2/3 / 6/7 + 3(3^2)
=2/3 * 7/6 + 3(9)
= 7/9 + 27
= 7/9 + 243/9
= 250/9
answer is a. 250/9
We will start off working on the right hand side.
<span>cot x - tan x </span>
<span>= [cos x / sin x] - [sin x / cos x] </span>
<span>= [(cos x)^ 2 - (sin x)^2] / [sin x cos x] </span>
<span>This is where it gets a bit tougher if you do not have your formula list with you. </span>
<span>(cos x)^ 2 - (sin x)^2 = cos(2x) </span>
<span>sin 2x = 2 sin x cos x </span>
<span>Note that by arranging the second formula, we will have sin x cos x = (1/2) sin 2x </span>
<span>Hence, we will get: </span>
<span>[(cos x)^ 2 - (sin x)^2] / [sin x cos x] </span>
<span>= [cos 2x] / (1/2)[sin 2x] </span>
<span>= 2[cos 2x] / [sin 2x] </span>
<span>= 2cot 2x </span>
We are given two points: (-1, -1) and (1, -4). Slope is calculated as the change in y over the change in x, or rise over run.
The change in y is the difference of the two y coordinates (it doesn't matter the order): -1 - (-4) = 3
The change in x is the difference of the two x coordinates (this order depends on the order that you subtracted the y coordinates; they must be the same order): -1 - 1 = -2.
So, the slope is 3/-2
Answer: -8+61 = 53 and 6+61 = 67