Monday

July 28, 2014

July 28, 2014

Posted by **Stranger** on Monday, March 18, 2013 at 3:39am.

- Trignometry -
**Steve**, Monday, March 18, 2013 at 4:23amIf we let x = ∠MBN and y=∠ABM=∠NBC, then

x+2y = pi/2

sin x = sin(pi/2-2y) = cos 2y = 1-2sin^2 y

Now, siny = 1/√5, so

sinx = 1 - 2(1/5) = 3/5

a+b=8

**Related Questions**

vmps - ABCD is a square where M and N are midpoints of AD and CD , respectively...

Trignometry - The angles in triangle ABC satisfy 6sin∠A=3√(3)sin&#...

maths - The angles in triangle ABC satisfy 6sin∠A=3√3sin∠B=2&#...

geometry - ABCD is a square of side length 1. E , F , G and H are the midpoints ...

heeeeeelp math - In a tetrahedron ABCD, the lengths of AB, AC, and BD are 6, 10...

helllllppp math - In a tetrahedron ABCD, the lengths of AB, AC, and BD are 6, 10...

geometry - The angles in triangle ABC satisfy 6sin∠A=3√3sin∠B=...

Math - Let S(n) denote the sum of digits of the integer n. Over all positive ...

Trigonometry question? - Let ABCD be a square, and let M and N be the midpoints ...

geometry...TRIANGLE - ABCD is a quadrilateral with ∠ADC=∠ACD, ∠...