Posted by john 2020 on Monday, March 8, 2010 at 10:40pm.
draw a 45 45 90 triangle with equal legs = 1
hypotenuse^2 = 1^2+1^2
h^2 = 2
h = sqrt 2
then cos 45 = 1/sqrt2 = sqrt 2/2
Related Questions
precalculus - find all solutions of each equations a) cos2x=square root of 3/2 b...
Precalculus - Find the exact value of sin 15°. I got square root of 2-...
Trig - 1. Establish the identity: sin(theta+3pi/2)=-cos(theta) 2. Find the exact...
Algebra II - Multiple Choice (theta) means the symbol 0 with the dash in it. 1.)...
Math- Trig - 1. Determine the exact value of cos^-1 (pi/2). Give number and ...
Math - Rationalize the denominator. Assume that all expressions under radicals ...
Trig functions and such - 1)Find the exact value of cot(-315) A)1 B)square root ...
math - There are no typos and no work b/c I don't know how to do them. ...
Precalculus - PLEASE HELP ME WITH THESE QUESTION AS MUCH AS POSSIBLE!! Evaluate...
mathematics - Given that A + B = 120 degrees and cosA + cos B = 1 divided by ...
For Further Reading
