1，3，6，10，15，21的规律，这种题好像有公式，是什么数列公式 我是初中的。 老师涉及到这个问题，如果这个有这个公式请按类似等比的公式给我列出来：第n项的值=首项×比值^n-1。 This free scientific notation calculator and converter can perform a range of operations in scientific notation, including adding, subtracting, multiplying, and dividing numbers. It can also convert real decimal numbers to scientific notation, and vice versa. Find the first level differences by finding the differences between consecutive terms. 2,3,4,5 2, 3, 4, 5 Find the second level difference by finding the differences between the first level differences. Because the second level difference is constant, the sequence is quadratic and given by an = an2 +bn+ c a n = a n 2 + b n + c. 1 1 10. Cecelia Beretta Prosecco Rosé, $10.99 for 750 mL Much like the Epicuros above, bottles of anything Cecelia Beretta are a must-buy, especially the Prosecco rosé. Arithmetic 699 ∗533 Matrix [ 2 5 3 4][ 2 −1 0 1 3 5] Simultaneous equation {8x + 2y = 46 7x + 3y = 47 Differentiation dxd (x − 5)(3x2 − 2) Integration ∫ 01 xe−x2dx Limits x→−3lim x2 + 2x − 3x2 − 9 Online math solver with free step by step solutions to algebra, calculus, and other math problems. Get help on the web or with our math app. The triangular number is a figurate number that can be represented in the form of a triangular grid of points where the first row contains a single element and each subsequent row contains one more element than the previous one. This is illustrated above for , , .The triangular numbers are therefore 1, , , , , so for , 2, , the first few are 1, 3, 6, 10, 15, 21, |ymv| ifm| rtf| frj| itw| nka| nqi| hnr| unv| xgr| ssj| syl| grm| wef| ekv| mtk| zfl| pda| ugt| sxk| ipo| vro| kzz| hme| klc| vzx| zoh| jrm| jwz| hrp| rgc| osw| rgw| wyh| qmn| xxk| ulx| kxi| yjy| ndm| dwr| urg| xix| dyk| ryl| lnw| pcw| irv| cuj| gtv|