What special skill does a developer need to produce timely solutions for users

Which of the following “invisible” marks represents an inserted tab?

How is the number 372 written when expanded out to place values in the base 8 (octal) number system? a. 2 x 4 + 3 x 2 + 4 x 1 b. 3 x 64 + 7 x 8 + 2 x 1 c. 3 x 8 + 7 x 7 + 2 x 6 d. 3 x 100 + 7 x 10 + 2 x 1

Ac++an of of pi. in , pi is by : pi = 4 – 4/3 + 4/5 – 4/7 + 4/9 - 4/11 + 4/13 - 4/15 + 4/17 . ., to pi (9 ). , if 5 to pi,be as : pi = 4 - 4/3 + 4/5 - 4/7 + 4/9 = 4 – 1. + 0.8 - 0. + 0. = 3.. atoofbe to pi?