Approximate the area under the graph of​ f(x) and above the​ x-axis with​ rectangles, using the following methods with nequals4. ​f(x)equalseSuperscript xplus5 from xequalsminus2 to xequals2 ​(a) Use left endpoints. ​(b) Use right endpoints. ​(c) Average the answers in parts​ (a) and​ (b) ​(d) Use midpoints.