# New post in Trigonometry

## What's the difference between arccos(x) and sec(x)?

January 25th, 2023

## The magnitude of $|-\sin t + \cos t|$ is.

November 25th, 2022

## Expressions for $\sin(\arctan(x))$ and $\cos(\arctan(x))$ that do not contain trigonometric functions

August 20th, 2022

## How do you simplify cos^4(x) by using power reducing formulae?

August 19th, 2022

July 23rd, 2022

## finding the acute angle between two functions at first point of intersection

December 24th, 2022

## Determine the point in Quadrant 2 where the line $y= -3x$ interects the unit circle.

August 18th, 2022

## Trigonometry problem: How far below the surface of the hill is a point $38m$ down the tunnel?

December 9th, 2022

July 23rd, 2022

## Find the value of $6P_{10} - 15P_8 + 10P_6+7$ for $P_n=\sin^n x+\cos^n x$

November 21st, 2022

## Prove $\sin(A-B)/\sin(A+B)=(a^2-b^2)/c^2$

August 15th, 2022

August 1st, 2022

## use De Moivre's theorem to show that: $\cos(3\theta) = 4\cos(3\theta)-3\cos(\theta)$ and $\sin(3\theta) = 3\sin(\theta) - 4\sin(3\theta)$

August 13th, 2022

## Algebraically why is that $\cos(0) =1$?

August 15th, 2022

## Finding $\lim_{x \rightarrow \frac{1}{4} \pi } \frac{\tan x-\cot x}{x-\frac{1}{4} \pi }$.

September 23rd, 2022

July 22nd, 2022

## Find the value of $\sin(90-a)$

September 14th, 2022

## How do I evaluate $\cos(x) + \cos (2x) +\cos (3x) + ... + \cos (nx)$?

September 13th, 2022

July 21st, 2022

August 1st, 2022

August 1st, 2022

August 1st, 2022

August 1st, 2022

August 1st, 2022

August 1st, 2022

August 1st, 2022

## Signed angle between 2 vectors?

November 9th, 2020

## Verify the identiy, (cos(x+h) - sin x)/h = cos x * ((cos h - 1)/h)- sin x * (sin h /h)

October 10th, 2020

May 1st, 2020

August 1st, 2022