Wednesday

July 23, 2014

July 23, 2014

Posted by **Anand** on Saturday, January 26, 2013 at 2:19am.

- Maths -
**Damon**, Saturday, January 26, 2013 at 5:30amI assume you mean

cos^2 A + cos^2 B + cos^2 C

cos A = 0 this is a right triangle with right angle at A so cos^2 A =0

so

cos B = b/a

cos C = c/a

b = a cos B

c = a cos C

but b^2 + c^2 = a^2

a^2 cos^2 B + a^2 cos^2 C = a^2

so

cos^2 B + cos^2 C = 1

so

cos^2 A + cos^2 B + cos^2 C = 1

**Related Questions**

maths - If S=1/2^2cos1 + 1/cos1¤cos2+1/2^3 cos1 ¤cos2¤cos2^2 + .......... upto ...

Trig 3 - Why does 1 - COS2(Squared) _________________ COS2 = tan2

Calc - Which expression is equivalent to (sin x + 1)(sin x − 1)? A. cos2^x...

Pre Calculus - Find each product or quotient. Express the result in rectangular ...

Mathematics - 1. Show that Sin3 Theta - Cos2 Theta = (1 - Sin Theta)(4Sin^2 ...

Mathamatics - Solve the following trigonometry identities. a) 1-cos2(theta) = ...

Maths - What Is The closure of the set {cos1,cos2,cos3,cos4,...} under usual ...

trig - solve for exact value for x between 0 and 2 pie 3sin2(x)-cos2=2?

Advanced Functions/Precalculus - Trigonometry Questions 1. Solve the equation ...

trigonometry - if cosθ=2/3 and tanθ<0 find the exact value sin(&#...