Here's an alternative approach:
Find the sum of length, breadth & height of a cuboid whose whole surface area is 214 cm^2, with a base area of 42 cm^2, and with volume 210 cm^3.
You can't have cosine of an angle greater than 1. Did you mean cos Z = 5/7?
The side length of the cube will equal the diameter of the ball. The diameter of the ball is given by circumference/pi.
i.e. d = 264/pi cm
Can you take it from here?
Every even power of 9 ends in 1, every odd power ends in 9. There are 51 even powers (including 90) and 50 odd powers.
Summing these we get 51*1 + 50*9 = 501, so the sum ends in 1.
solve for X (A, B, & C are constants): arctan(C/X)=arcsin((A-X)/B)
Is this what you are looking for?
This is best tackled as follows:
2 + 4 + 6 + 8 + ... + 100 = 2*(1 + 2 + 3 + 4 + ... + 50)
The sum of the first n integers is given by n(n+1)/2 so the above sum becomes 2*50*51/2 = 50*51 = 2550
The sum of the first n integers is given by n*(n+1)/2
So you have n*(n+1)/2 = 10*n
Solve for n.
Correct.
The sum of the coefficients of a polynomial is just given by the sum of all the terms when x = 1. So to find it just set x = 1 in your expression.
+33666 
