1. 1+cos2A+cosA=cotA sin2A+sinA 2. sin2A = tanA 1+cos2A 3. sin2A = cotA 1-cos2A 4. sin2A-cos2A=secA sinA cosA 5. 1+sinA-cosA =tan A 1+sinA+cosA 2 THANK YOU!!
Last edited by sanikui; September 4th 2008 at 06:26 PM.
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Hello ! cos(2A)=cos^2(A)-sin^2(A) sin(2A)=2sin(A)cos(A) put in the above to get [2cos^2 (A)+cos(A)] / [2sin(A)cos(A)+sin(A)] Take cos(A) from numerator & sin(A) from denominatorcommon you get cot(A)
put 1+cos(2A)=2cos^2(A) for 2nd denom. 1-cos(2A)=2sin^2(A) for 3rd denom. sin(2A)=2sin(A)cos(A) for numerator and cancel common terms.
k...i got it....thx how about 4 n 5?
Hello, sanikui! Here's #4 . . . We have: . . .
multiply denominator with both numer. and denom. u will get RHS= / numerator denominator cancel =>RHS Now u remember 3rd Question u will get dere may be shortcut for this! sOrRy for I went offline ys'trday after 3rd
Thx ADARSH and Soroban,i try my best~!
Question 5 i think no nid multiply denominator with both numer and denom. Just use half-angles formulas...then can do it.
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