Write a java program that prompts the user for the diameter of a circle and an x-increment "dx" (both in centimeters), then calculates and displays the area of the circle in square centimeters using a Riemann Sum. To find the area of the circle using a Riemann sum, first, find the area of one quadrant by dividing the quadrant into rectangles, each of width "dx" (as in "delta-x", which means "change in x"), and then use the Pythagorean Theorem to find the "y" value at each "x" value.

y = sqrt(r^2 - x^2)

Multiply "dx" by "y" to get the area of the rectangle at that "x" value (see attached diagram). Add the areas of the rectangles together, and you have the area of the quadrant. To obtain the area of the entire circle, multiply the quadrant's area by four.

The program should use a for loop to do the calculations.

All variables should be of type double.

It should also use at least 2 methods.

In this lab, you complete a prewritten c++ program for a carpenter who creates personalized house signs. the program is supposed to compute the price of any sign a customer orders, based on the following facts: the charge for all signs is a minimum of $35.00. the first five letters or numbers are included in the minimum charge; there is a $4 charge for each additional character. if the sign is made of oak, add $20.00. no charge is added for pine. black or white characters are included in the minimum charge; there is an additional $15 charge for gold-leaf lettering. instructions ensure the file named housesign.cppis open in the code editor. you need to declare variables for the following, and initialize them where specified: a variable for the cost of the sign initialized to 0.00 (charge). a variable for the number of characters initialized to 8 (numchars). a variable for the color of the characters initialized to "gold" (color). a variable for the wood type initialized to "oak" (woodtype). write the rest of the program using assignment statements and ifstatements as appropriate. the output statements are written for you. execute the program by clicking the run button. your output should be: the charge for this sign is $82. this is the code, // housesign.cpp - this program calculates prices for custom made signs. #include #include using namespace std; int main() { // this is the work done in the housekeeping() function // declare and initialize variables here // charge for this sign // color of characters in sign // number of characters in sign // type of wood // this is the work done in the detailloop() function // write assignment and if statements here // this is the work done in the endofjob() function // output charge for this sign cout < < "the charge for this sign is $" < < charge < < endl; return(0); }

Write a function balancechemical to balance chemical reactions by solving a linear set of equations. the inputs arguments are: reagents: symbols of reagents in string row array products: symbols of products in string row array elements: elements in the reaction in string row array elcmpreag: elemental composition of reactants in two dimensional numeric array elcmpprdcts: elemental composition of prducts in two dimensional numeric array hint: the first part of the problem is setting up the set of linear equations that should be solve. the second part of the problem is to find the integers from the solution. one way to do this is to mulitiply the rational basis for the nullspace by increasing larger integers until both the left-and right-side integers exist. for example, for the reaction that involves reacting with to produce and : reagents=["ch4", "o2"]; products =["co2", "h2o"]; elements =["c","h", "o"] elcmpreag=[1,4,0;

How is the brightness of oled of the diaplay is controled