Sar asked in Science & MathematicsMathematics · 1 decade ago

Is there and easier way to do trig identities?

Any hints or tips?

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  • Edward
    Lv 7
    1 decade ago
    Favorite Answer

    Yes

    Observe

    sin(x) cos(x) tan(x) cot(x) sec(x) csec(x)

    1/sin(x)=csec(x)

    1/cos(x)=sec(x)

    1/tan(x) =cot(x)

    also

    sin(x)/cos(x)=tan(x)

    sin^2(x)+cos^2(x)=1

    These are the basic level 1 (just kidding but if you got that you got 40% of the bulk)

    Double angle

    sin(2x)=2sin(x)cos(x)

    cos(2x)=cos^2(x)-sin^2(x)

    Knowing that puts you into 65-70th percentile.

    Then you use these to derive additional 10-15%

    Oh yes!

    What about

    sin(x+y)=? see rteference or math tables

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  • 1 decade ago

    Start on the side that looks the most complicated.

    Use well know identities that help you to isolate to just a single trig function.

    Just keep trying and you'll get it finally.

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  • 1 decade ago

    learn

    tanx,cotx,cosecx, secx, sin2x, cos2x

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  • 1 decade ago

    hard way-practise

    clever way- (a+b)^3

    =(a+b)*(a+b)*(a+b)

    =we can multiply each to get the formula

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