write as the sum of terms, and then find the sum:

Question

upper bond (5)

lower bond (j = 2)

∑ (3j - j)²

 

Answer 1

You are just plugging in the numbers here for j=2, 3, 4, and 5 and adding those terms together.  That big fancy symbol is a Greek Sigma, and represents "sum".

 

Note also that 3j-j=2j, so you really only need to do the math for (2j)², or 4j² (unless your problem is a typo)

• j=2, 4(2)²=4*4=16
• j=3, 4(3)²=4*9=36
• j=4, 4(4)²=4*16=64
• j=5, 4(5)²=100
• Therefore the sum is 16+36+64+100=216