# Search Results

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Search options not deleted user 96110
7 results

Trigonometric functions (both geometric and circular), relationships between lengths and angles in triangles and other topics relating to measuring triangles.

1 vote
827 views

### Deducing $\sin x + \cos x \ge 1$ from $(\sin x + \cos x)^2 = 1 + 2 \sin x \cos x$

So in trig, say I have an acute angle $X$. And one can intuitively conclude that $\sin x + \cos x \ge 1$, but how does the fact that $$(\sin x + \cos x)^2 = 1 + 2 \sin x \cos x$$ tell me that it is tr …
• 1,361
4k views

### What is the radius of a circle inscribed in a 6-8-10 triangle?

Here's me trying to do the problem. http://s10.postimg.org/bwwliium1/image.jpg So this problem was from a textbook and it was in the chapter of the theorem: If $\theta$ is the angle subtended by a c …
• 1,361
1 vote
248 views

Here's me trying to do that. After $\frac{BP}{AC} = \frac{BP}{BC} \frac{BC}{AC} = \cos(\alpha - \beta)\tan(\beta)$, I didn't know what to do next. Theoretically, it should become $\cos(\alpha)\sin … • 1,361 2 votes 4 answers 2k views ### Upon multiplying$\cos(20^\circ)\cos(40^\circ)\cos(80^\circ)$by the sine of a certain angle... So if$P = \cos(20^\circ)\cos(40^\circ)\cos(80^\circ)$, I can multiply$P$by$\sin(X)$so that the entire expression reduces to something manageable. I then take the simplified product and divide it … • 1,361 3 votes 1 answer 2k views ### If$A + B + C = \pi$, then show that$\sin(A) + \sin(B) + \sin(C) = 4\cos\frac{A}{2}\cos\fra... [duplicate]

So i have $A + B + C = \pi$ $$\frac{A}{2} + \frac {B}{2} + \frac{C}{2} = \frac{\pi}{2}$$ $$4\cos\left(\frac{-B-C + \pi}{2}\right)\cos\left(\frac{-A -C + \pi}{2}\right)\cdots$$ And I doubt this lea …
• 1,361