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anonymous

  • 5 years ago

Please help me to prove Sin^2 -Cos^2 =1 .....

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  1. anonymous
    • 5 years ago
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    Sin^2(x)-Cos^2(x) does not equal one.

  2. anonymous
    • 5 years ago
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    \[ \sin ^{2} - \cos ^{2} =1 \] Please Prove this....

  3. anonymous
    • 5 years ago
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    \[\sin ^2(x)-\cos^2(x)\neq1\]

  4. anonymous
    • 5 years ago
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    But I ve got this from a web site.... Here's the address.... Please go there and see whats wrong with it... .... http://www.cramster.com/practice-problems-p25-0-0-0-0-0-39167-0-cpi0-0.aspx

  5. anonymous
    • 5 years ago
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    Which number?

  6. anonymous
    • 5 years ago
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    In the Practice-3 Question set.... number 4

  7. anonymous
    • 5 years ago
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    \[\sin ^2(x)+\cos^2(x)=1\]\[\sin ^2(x)-\cos^2(x)=-\cos(2x)\]

  8. anonymous
    • 5 years ago
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    Oh.... Friutless can you please explain this farther......

  9. anonymous
    • 5 years ago
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    Which one?

  10. anonymous
    • 5 years ago
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    Your reply for the Question I 've asked.....

  11. anonymous
    • 5 years ago
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    ok well this can be proved for sin(x)^2 + cos(x)^2 = 1 because this identity is true. you want to prove this? THE IDENTITY sin(x)^2 - cos(x)^2 = 1 IS NOT TRUE. DON'T THINK ABOUT WHAT THE WEBSITE SAYS. IT IS NOT TRUE. PERIOD. what would you like help proving?

  12. anonymous
    • 5 years ago
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    It is asking which one from the choices is correct. It is obviously not D.

  13. anonymous
    • 5 years ago
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    (i) is the correct answer.

  14. anonymous
    • 5 years ago
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    Ok prove this one then... \[\sin ^{8}A-\cos ^{8}A = (\sin ^{2}A-\cos ^{2}A) (1- 2 \sin ^{2}A \cos ^{2}A)\]

  15. anonymous
    • 5 years ago
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    apply the FOIL method to the right side (expand it) \[-\cos^2(A)+\sin^2(A)+2 \cos^4(A) \sin^2(A)-2 Cos^2(A) Sin^4(A)\]

  16. anonymous
    • 5 years ago
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    Replace the first two functions with an identity, and factor the rest.

  17. anonymous
    • 5 years ago
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    Hmmmm.... friutless in which grade you're studying... ?

  18. anonymous
    • 5 years ago
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    high school

  19. anonymous
    • 5 years ago
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    In which country...?

  20. anonymous
    • 5 years ago
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    usa

  21. anonymous
    • 5 years ago
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    Really.... then I think you have done something similar to the syllbus of London A/L isn't you?

  22. anonymous
    • 5 years ago
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    I am asking this from you because I am a student who has just started doing A/L s in Sri Lanka (somewhat similar to London A/L ). so I don't know the FOIL method..... So I can't understand you're reply.....

  23. anonymous
    • 5 years ago
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    Given (x-a)(y-b), applying FOIL yeilds xy-xb-ay+ab

  24. anonymous
    • 5 years ago
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    Do the same on the trigonometric expressions

  25. anonymous
    • 5 years ago
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    wow... I've got the right teacher here... thank you....

  26. anonymous
    • 5 years ago
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    did you get the left side from this method?

  27. anonymous
    • 5 years ago
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    \[Sin ^{8}A-\cos ^{8}A=( \sin ^{2}A-\cos ^{2}A)(\sin ^{6}A+\cos ^{6}A)+\sin ^{2}Acos ^{6}A-\cos ^{2}Asin ^{6}A\] Here's what I've done....... but I've stucked in it please try this also....

  28. anonymous
    • 5 years ago
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    Please help me......

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