![Let f: R ->[0,pi/2) be defined by f(x)=tan^(-1)(x^2+x+a)dot Then the set of values of a for which f is onto is (a)(0,oo) (b) [2,1] (c) [1/4,oo] (d) none of these Let f: R ->[0,pi/2) be defined by f(x)=tan^(-1)(x^2+x+a)dot Then the set of values of a for which f is onto is (a)(0,oo) (b) [2,1] (c) [1/4,oo] (d) none of these](https://d10lpgp6xz60nq.cloudfront.net/web-thumb/27841_web.png)
Let f: R ->[0,pi/2) be defined by f(x)=tan^(-1)(x^2+x+a)dot Then the set of values of a for which f is onto is (a)(0,oo) (b) [2,1] (c) [1/4,oo] (d) none of these
![Dave Richeson on Twitter: "Euler proved that π/4=arctan(1/2)+arctan(1/3), which can be used for computing digits of π (using the arctangent series). I wondered if I could prove it without using a trig Dave Richeson on Twitter: "Euler proved that π/4=arctan(1/2)+arctan(1/3), which can be used for computing digits of π (using the arctangent series). I wondered if I could prove it without using a trig](https://pbs.twimg.com/media/DhXRIQiX0AA9cMz.jpg)
Dave Richeson on Twitter: "Euler proved that π/4=arctan(1/2)+arctan(1/3), which can be used for computing digits of π (using the arctangent series). I wondered if I could prove it without using a trig
![The Pi Symbol Mathematical Constant Irrational Number Greek Letter And Many Formulas Background Stock Illustration - Download Image Now - iStock The Pi Symbol Mathematical Constant Irrational Number Greek Letter And Many Formulas Background Stock Illustration - Download Image Now - iStock](https://media.istockphoto.com/id/1045662208/vector/the-pi-symbol-mathematical-constant-irrational-number-greek-letter-and-many-formulas.jpg?s=612x612&w=is&k=20&c=w-gITtlMxTno1FDaNBJViMuyHma59Oxqk7yU8HZ2Qmo=)
The Pi Symbol Mathematical Constant Irrational Number Greek Letter And Many Formulas Background Stock Illustration - Download Image Now - iStock
![SOLVED: 1. tan a = 8/15, pi < a < 3pi/2; cos b =-5/13, pi/2 < b Find sin(a+b) A) 140/221 B) 220/221 C) -220/221 D) 171/221 E) -21/221 F) -140/221 2. SOLVED: 1. tan a = 8/15, pi < a < 3pi/2; cos b =-5/13, pi/2 < b Find sin(a+b) A) 140/221 B) 220/221 C) -220/221 D) 171/221 E) -21/221 F) -140/221 2.](https://cdn.numerade.com/ask_previews/5ef497e0-7570-4594-98c3-d530cf2626d9_large.jpg)
SOLVED: 1. tan a = 8/15, pi < a < 3pi/2; cos b =-5/13, pi/2 < b Find sin(a+b) A) 140/221 B) 220/221 C) -220/221 D) 171/221 E) -21/221 F) -140/221 2.
![trigonometry - Since $\tan(25\pi/2)$ is undefined, and $\cot x = \frac{1}{\tan x}$, then why isn't $\cot(25\pi/2)$ undefined instead of $0$? - Mathematics Stack Exchange trigonometry - Since $\tan(25\pi/2)$ is undefined, and $\cot x = \frac{1}{\tan x}$, then why isn't $\cot(25\pi/2)$ undefined instead of $0$? - Mathematics Stack Exchange](https://i.stack.imgur.com/tFfsY.gif)