(1-x)y"-4xy'+5y=cosx
1 answer:
You might be interested in
Answer:
5 + 8 + 11 + 10 = 34
Step-by-step explanation:
The lengths of the horizontal and vertical sides are easily determined. The slant side is seen to be the hypotenuse of a 3-4-5 triangle (times 2), so is 10 units long. The perimeter is the sum of the side lengths:
5 + 8 + 11 + 10 = 34
_____
You can always estimate the length of the hypotenuse of a right triangle as being between 1 and 1.5 times the length of the <em>longest</em> side. Here, the longest side of the right triangle whose hypotenuse is of interest is 8 units, so the hypotenuse will be between 8 and 12 units long. That means the perimeter of the blue trapezoid will be between 32 and 36, a guess of sufficient accuracy to allow you to choose the correct answer.
In a figure like this, you can also measure the hypotenuse on the grid. Using a compass, ruler, or a piece of paper with a couple of marks, you can rotate the slant length so that it corresponds to a vertical or horizontal grid line. Then the length of it is easily estimated to good accuracy. (See the second attachment.) As we said in the previous paragraph, even poor accuracy is sufficient to choose the correct answer.
Answer:
See attached
Step-by-step explanation:
When there is a lot of repetitive calculation to do, I like to let a spreadsheet or graphing calculator do it. The attached shows a spreadsheet that computes all the values you're asked to find.
For a linear equation in standard form, ax +by = c
- the x-intercept is: c/a
- the y-intercept is: c/b
- the slope is: m = -a/b
Of course, the slope-intercept form of the equation is ...
y = (slope)·x + (y-intercept)
and the values of the various points on the graph can be computed from that equation.
___
You will note that the last two equations describe the same line.
_____
<em>Note on spreadsheet formulas</em>
When you put the formulas into the spreadsheet, make sure to fix the column number or row number of the values you're computing, as appropriate. For example, the y-values in the different columns always use the slope from the slope column (fixed), the y-intercept from that column (fixed), and the x-value from the top row (fixed). If you make the cell references relative instead of fixed, you will get wrong answers.
