這是怎麼得到21.8的？我自己去查了反三角函數感覺我還缺一些前置基礎，所以希望可以有計算過程我之後自己研究

27 The diagram shows triangle ABP inside the regular hexagon ABCDEF D 860² - 4 2 5 AB = 5 cm Work out the size of angle PAF Give your answer correct to 3 significant figures. BP = 2 cm E Angle ABP = 90° (6-2)-180 6/92= 120 =720 F Diagram NOT accurately drawn X+3 6+4 = Do x+y=90 442=120 *X-2=-

51題，解答九分之一那邊，為何是cot3x的三次方而不是一次方，為何是九分之一不是三分之一？

Finding an Indefinite Integral In Exercises 49–58, find the indefinite integral. Use a computer algebra system to confirm your result. 49. cot 2x dx 50. tan Soor foset X X sec4 4 4 dx 51. csc4 3x dx 52. cores X X cot? csc4 – dx 2 2

要問第1和4題～ 然後請幫我看第2和3題的答案對不對？ 麻煩幫我解釋謝謝

l) hin 189 tot 1x tant - hec 44 + Cat 46 tsin to 12 m. The cost fanso xcotto Dotex content Cobbo's zobe | | (?) hin 54 x (hC54 - tanisl ther's l-hin 42 xhec48 =hinx 77954 - tans it (tan's +1) - computer Eto tanto +/- Co to +1 =Cache *j ton 38% tanisz-cot 184 Chetiga = (he138 -1) (sec52-1)- (C2C78-1) + Cue18 = heisst hee's? hec 35-hee's 2 + 1 - ChcX8 + 1 + che

How?

of primary school children showed that between 55% and 65% owned a mputer, between 709 and 80% owned a mobile phone and fewerthan 5% ofthese iems. ge ofthe children owned both a laptop computer and a mobile phone? 415% and 30%