# trigonometry

Prove :
1 + Sin2A/ Cos2A = CosA + SinA / CosA- SinA

1. 👍 0
2. 👎 0
3. 👁 1,318
1. How about some parentheses, so we can tell what's what?

As it stands, it means

1 + tan2A = cosA + tanA - sinA

which is clearly false

1. 👍 0
2. 👎 0
2. Clive probably meant:
(1+sin 2A)/cos 2A = (cosA + sinA)/(cosA - sinA)

LS = (sin^2 A + cos^2 A + 2sinAcosA)/(cos^2 A - sin^2 A)
= (cosA + sinA)/( difference of squares)
= ...

I am sure you can take it from there

1. 👍 0
2. 👎 0
3. I AM WRONG >

1. 👍 0
2. 👎 0
4. if x = rsinAcosC,y=rsinA sinC and z = rcosA,then prove that r2= x2+y2+z2

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Trigonometry

If sinA + sinB = a and cosA + cosB = b, find the value of tanA-B/2

2. ### maths

Prove SinA/1-CosA = CosecA + CotA

3. ### Math

if sinA+sinB=x and cosA-cosB=y then find tan[(A-B)/2]

4. ### Math

prove that sinA/(1+cosA) + (1+cosA)/(sinA) = 2cosecA

1. ### maths

sinA+cosA=p and secA+CosecA=q then show that q[p^2-1]=2p

2. ### math

if cos(B-C)+cos(C-A)+cos(A-B)=-3/2 then prove that cosA+cosB+cosC=O and sinA+sinB+sinC=O after that prove that cos(B-C)=cos(C-A)=cos(A-B)=-1/2

3. ### maths

Prove that in any triangle ABC Sin2A+Sin2B+Sin2C/SinA+SinB+SinC=8Sin(A/2)Sin(B/2)Sin(C/2)

4. ### maths

if sinA+cosA=1/5, then a value of tanA/2 satisfies which of the equation? a. 2x^2-x-1 b.x^2-2x-3=0 c.2x^2-5x-3=0 d. 2x^3-7x^2+2x+3=0

1. ### Maths

Cos^2A/sinA-cosecA+sinA=0 Prove lHS =RHS

2. ### Maths

Given that sinA=2/5 and that A is obtuse,find the value of cosA. 👍 0 👎 0 👁 25 asked by Raj yesterday at 4:18am sinA = 2/5, so cosA = √21/5 But A is in QII, so cosA = -√21/5 👍 0 👎 0 posted by oobleck yesterday at

3. ### maths

If cosA + sinA= root2 cosA Show that cosA - sinA= root2 sinA

4. ### trig

if 8 tan Q=15 then sinA-cosA=?