Monday

January 26, 2015

January 26, 2015

Posted by **olivia** on Wednesday, March 28, 2012 at 9:50am.

find sinA, sin2A, cos2A

- precal- PLEASE HELP! -
**Reiny**, Wednesday, March 28, 2012 at 11:16amcosA = 4/5 or opposite = 4, hypotenuse = 5

you should recognize the 3-4-5 triangle,

then sinA = 3/5

sin 2A = 2sinAcosA = 2(3/5)(4/5) = 24/25

cos 2A = cos^2 A - sin^2 A

= 16/25 - 9/25 = 7/25

- precal- PLEASE HELP! -
**olivia**, Sunday, April 1, 2012 at 10:21pmthank you.

**Answer this Question**

**Related Questions**

further Mathematics - Let A=(cosA -sinA) (sinA cosA) show that A^2=(cos2A sin2A...

math - how do you solve this.prove: cos2A plus cosA divided by sin2A minus sinA ...

trig - Prove: 1/cos2A+sin2A/cos2A=sinA+cosA/cosA-sinA

trig - Prove: 1/cos2A+sin2A/cos2A=sinA+cosA/cosA-sinA

MathS triG - 1 .If tanA=1/3 and tanB=1/7 (both A and B are acute),calculate ...

maths Pls help trig - 1 .If tanA=1/3 and tanB=1/7 (both A and B are acute),...

Mathematics - If cosA is equal to 12/13 where 0 degrees is less than A less than...

Math - Find angle A if it is greater than or equal to 0 degrees and smaller than...

Statistics - Let Y be a random number between 0 and 1 generated by an idealized ...

Maths - Hi, can someone give me the answer to this question: secA-tanA=1/4. Find...