$$S_n=\frac{a_1\left(1-r^n\right)}{1-r}\ ,\ r\ne1$$

$$S_n=\frac{a_1\left(1-r\right)^n}{1-r}\ ,\ r\ne1$$

$$S_n=\frac{a_1\left(r^n-1\right)}{1-r}\ ,\ r\ne1$$

$$S_n=\frac{a_1\left(r-1\right)^n}{r-1}\ ,\ r\ne1$$

$$\frac{31}{2}$$

$$\frac{33}{2}$$

$$\frac{61}{2}$$

$$\frac{63}{2}$$

$$1,023$$

$$1,024$$

$$2,047$$

$$2,048$$

$$31$$

$$33$$

$$93$$

$$96$$

$$\frac{511}{256}$$

$$\frac{512}{256}$$

$$\frac{1,023}{512}$$

$$\frac{1,024}{512}$$

$$2+\ 4+\ 6+\ 8+\ ...$$

$$3\ +\ 6+\ 12\ +\ 24+\ ...\$$

$$9+3+1+\frac{1}{3}+...$$

$$16+8+4+2+...$$

$$2$$

$$\sqrt[]{2}$$

$$\frac{1}{2}$$

$$\frac{1}{\sqrt[]{2}}$$

$$384\ บาท\$$

$$1,384\ บาท$$

$$10,768\ บาท$$

$$17,768\ บาท$$

ไม่มีข้อถูก

$$a_1=\frac{27}{32}$$

$$r=\frac{2}{3}$$

$$a_3+a_4=\frac{7}{8}$$

ต่อไปนี้คือสิ่งที่คุณต้องการ

ไม่มีข้อถูก

$$\frac{569}{64}$$

$$\frac{1,069}{64}$$

$$\frac{2,069}{64}$$

$$\frac{3,069}{64}$$

$$511$$

$$1,023$$

$$2,047$$

$$4,095$$

$$S_n=\frac{\left(2\right)\left(\left(-2\right)^n-1\right)}{2-1}$$

$$S_n=\frac{\left(-2\right)\left(2^n-1\right)}{2-1}$$

$$S_n=\frac{\left(-2\right)\left(1-2^n\right)}{1-\left(-2\right)}$$

$$S_n=\frac{\left(2\right)\left(\left(-2\right)^n-1\right)}{1-\left(-2\right)}$$