SOLUTION: If sin(A)=-5/13. Find:
1. cos(2A)
2. sin(2A)
2. Cos(4A)
Algebra.Com
Question 1110589: If sin(A)=-5/13. Find:
1. cos(2A)
2. sin(2A)
2. Cos(4A)
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
If sin(A)=-5/13. Find:
1. cos(2A)
2. sin(2A)
2. Cos(4A)
--------------------
Step 1, find cos(A)
cos(A) = sqrt(1 - sin^2) = 12/13 or -12/13
The sine is negative in Q3 and Q4. The cosine is negative in Q3 and + in Q4, so the sign and quadrant cannot be determined.
-----
sin(2A) = 2sin(A)*cos(A)
---
cos(2A) = sqrt(1 - sin^2(2A))
---
cos(4A) = cos^2(2A) - sin^2(2A)
RELATED QUESTIONS
A is a reflexive angle whose sin is -5/13. Find:
1. sin (2A)
2. cos (2A)
3. sin (4A
(answered by Alan3354)
cos^4A-sin^4A=cos^2A-sin^2A (answered by Alan3354,ikleyn)
cos^4A+Sin^2A=Sin^4A+Cos^2A (answered by ikleyn)
If ∠A is ACUTE and cos A = 4/5 find sin A, cos 2A, sin 2A, and tan... (answered by ikleyn)
Cos 2A + 1/Cot A = Sin... (answered by Alan3354)
Prove that
{{{ Cos^4A - Sin^4A = 1 - 2Sin^2A... (answered by lwsshak3)
Find sin A, cos A, cos 2A, and sin (A/2) if the measure of angle A is 37... (answered by MathLover1)
simplify the given expressions:
a)2 sin^2α − 1/sina + cosa
b) cos^2a -... (answered by greenestamps)
simplify the given expressions:
a) (2 sin^2α − 1)/(sina + cosa)
b) (cos^2a -... (answered by MathLover1)