\nπ<\/td>\n 0<\/td>\n (0, π)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/p>\n
notice that my θ<\/em> did not go all the way to 2π. we’ll talk about why in a moment. for now though, let’s plot those points.<\/p>\nplot of sample points for r<\/em> = 1 + cos θ<\/em> in the domain [0, π]<\/figcaption><\/figure>\nthe general shape should be clear. we’ll draw a smooth curve starting at polar point (2, 0) and connecting the dots in a counterclockwise direction.<\/p>\n
<\/p>\n
now to finish our graph we could list out the values of r<\/em> for π < θ<\/em> ≤ 2π repeating the same procedure as above.<\/p>\nor<\/em>, we could use our knowledge of the cosine function and save a lot of work!<\/p>\nremember that cos x<\/em> has mirror symmetry about x<\/em> = π. this means that the values of cos x<\/em> in the interval [π, 2π] will simply rise back up like a mirror image of those in [0, π].<\/p>\nit may be harder to see what happens in the polar plot, but just imagine the curve bouncing back outward as you complete the journey around the full circle. take a look at the complete graph below.<\/p>\nthis graph is called a cardioid<\/strong> becausee of its resemblance to a heart.<\/figcaption><\/figure>\nwhat about the calculator?<\/h3>\n graphing by hand is, of course, very time consuming. however if you’re working in a section of the exam that allows a graphing calculator, then i have good news for you.<\/p>\n
your calculator understands polar functions!<\/p>\n
on most graphing calculators there is setting that puts you into polar mode. then whatever you graph will be interpreted as a polar function.<\/p>\n
derivatives of polar functions<\/h2>\n this wouldn’t be calculus unless we started talking about derivatives<\/em>!<\/p>\nsuppose you want to find the slope of a polar curve. then the following derivative formula is what you need.<\/p>\n
<\/p>\n
example — slope of a polar function<\/h3>\n consider the cardioid function, r<\/em> = 1 + cos θ<\/em>. what is the slope at θ<\/em> = π\/4?<\/p>\nlet’s use the formula to find out. here, f<\/em>(θ<\/em>) = 1 + cos θ<\/em>.<\/p>\n <\/p>\n
polar area formula<\/h2>\n finally, you can use the following formula to work out the area within a polar curve.<\/p>\n
<\/p>\n
typically on the ap calculus bc exam, a question may ask for the proper setup of the area integral. on the other hand, if you are in a calculator-permitted section, then you can easily find the area by numerical integration.<\/p>\n
example — area of the cardioid<\/h3>\n let’s use our running example and find the area within the cardioid. remember, f<\/em>(θ<\/em>) = 1 + cos θ<\/em> describes the cardioid for 0 ≤ θ<\/em> ≤ 2π.<\/p>\n <\/p>\n
summary<\/h2>\n here are a few points to remember about polar functions.<\/p>\n
\nthis topic only shows up on the ap calculus bc exam.<\/li>\n know how to plot polar points (r<\/em>, θ<\/em>) as well as sketch polar functions r<\/em> = f<\/em>(θ<\/em>).\n<\/li>\nknow the polar derivative formula (for finding slope).<\/li>\n know how to setup the polar area formula.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"polar functions show up on the ap calculus bc exam. learn about polar functions and maximize your score on the the exam by reading this review!<\/p>\n","protected":false},"author":223,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[240],"tags":[241],"ppma_author":[24932],"acf":[],"yoast_head":"\n
ap calculus bc review: polar functions - magoosh blog | high school<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n