Find the diameter of a circle with the given dimensions r=13 cm

Which operation should be performed first according to the order of operations? 44 • 2 – [(5 + 20 • 3) – 12] + 16 ÷ 2 5 + 20 20 • 3 16 ÷ 2 44 • 2

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

Will give brainliest sum of arithmetic series (sigma notation) find the numerical answer to the summation given below. (image shown below)