By the distance formula, the distance from (x,y) to (0,0) is r = √[(x-0)2 + (y-0)2] = √[x2+y2]. So, x2 + y2 = r2 By definition, cosθ = x/r and sinθ = y/r So, cos2θ + sin2θ = (x/r)2 + (y/r)2 = (x2+y2)/r2 = r2/r2 = 1 Upvote •...
已知函数 ,其函数 的部分图象如图所示,则函数 的解析式为()
The absolute value of a number a is represented as |a| and is the positive numerical value of a irrespective of the sign of a. Thus, if a=−2,|a|=|−2|=2. Note that this is also the absolute value of the number 2.
What is the range of the function f (x) = (x - 1)^2, when the domain is {-5, 0, 5}? What is the range of the function y = -2x + 6 with the domain being -1? Given f(x) = x^2 + 3x - 7, what is the range of the function when the domain is (-3, 2, 5)?
Why is sec(pi)x = (1/pi)sec x? Why does e^{-\infty}=0? Why is e^pi greater than pi^e? Explain why \frac{\sin x}{x} \leq 1 for -1 \leq x \leq 1, x \neq 0 . Why are we able to transform 4x-2(x-5)=3x into 4x-2x+10? Why is 7 + x not a monomial? Why...
① ;② 。 (2)实验室用氯酸钾制取氧气,应选用的发生装置是 ,(填字母序号,下同),若要收集一瓶干燥的氧气,应选择的收集装置是 。 (3)实验室用H 2O 2溶液和MnO 2混合制氧气,其中MnO 2起 作用。同学们利用B和F装置,通过排水量来测定生成氧气的体积,反应结束后,发现量筒内...
1/(4000000000000m.x)-2⋅3⋅0⋅0⋅0⋅sin^2xsin2x⋅cosωx 听录音,并朗读。 贝蒂:今天我上学迟到了。 妈妈:为什么?发生什么事了? 贝蒂:我坐公共汽车去的。 发生了一起交通 事故,交通非常拥堵。 但除了我,没有 人迟到。 也许我应该乘出租车去 上学。 妈妈:那是最舒服的方式,但也是最贵的...
故选D。51.A细节理解题。题干意为:根据文章,如果我们尝试新鲜事物,我们能根据第二段中 "It's always good to try new things beeausewhenwenwn[wwn][wn(w-w)w] er trytany eanswer is ‘We can't’"(尝试新事物总是好的,因为当我们尝试新事物时,我们在成长。如果我们从不尝试任何新的事物,我们...
(1) The post is not misstated. (c) is the odd one out isn't it? the given range for x is fine for the 1st two but not for (c) "arcsin" is misspelled as arccsin. what other carelessness is there? ask your teacher for a model answer - showing working. UPDATE:...
根据第二段A kind act makes someone who is sad feel better. It can also make ourselves feel good.善良的行为会让悲伤的人感觉好一些。它也可以让我们自己感觉良好。可知it指代前面提到的a kind act。故选C。(3)C.文章结构题。根据第一段But why and how does it ...