There are 2,500 grams in 2.5kg
-1 & 4. -1 x 4 = -4 and -1 + 4= 3
9 students, 4 are selected and order doesn't matter:
Go to the 9th row of the triangle (mind you the first row is 0), the 2nd is 1st row
9th row: 1 9 36 84 126 126 84 36 9 1
Now choose the 4th column (excluding the 1st , you will get 126 :
so 126 is the number of combination requested:
PROOF: ⁹C₄ = 9!/(9-4)! .4! = (9!)/5!.4! = 126
1. square both sides, a straight forward method.
<span>2. hand plot </span>
<span>3. calculator plot, not recommended.Let Y=sin x + cos x -1 </span>
<span>Y=0, find x=? </span>
<span>4. Substitute 1=sin^2(x) + cos^2(x) on the right hand side </span>
<span>Y1=sin^2(x) - sin(x) </span>
<span>Y2=cos^2(x) - cos(x) </span>
<span>Y1 + Y2=0, Y1=0, Y2=0, </span>
<span>a(a-1)=0, so, a=0, a=1, where a=sin(x), or cos(x), </span>
<span>so x=0, pi/2 </span>
<span>Have a good day!</span>
Answer: each moth He pays 5$ But 8 Months ❌= 280
5 x 8
