求证恒等式:(1+sinx)/cosx=tan(派/4+x/2);

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求证恒等式:(1+sinx)/cosx=tan(派/4+x/2);

求证恒等式:(1+sinx)/cosx=tan(派/4+x/2);
求证恒等式:
(1+sinx)/cosx=tan(派/4+x/2);

求证恒等式:(1+sinx)/cosx=tan(派/4+x/2);
左边=[sin²(x/2)+cos²(x/2)+2sin(x/2)cos(x/2)]/[cos²(x/2)-sin²(x/2)]
=[sin(x/2)+cos(x/2)]²/[cos(x/2)+sin(x/2)][cos(x/2)-sin(x/2)]
=[cos(x/2)+sin(x/2)]/[cos(x/2)-sin(x/2)]
上下除以cos(x/2)
=[1-tan(x/2)]/[1+tan(x/2)]
=[tan(π/4)-tan(x/2)]/[1+tan(π/4)tan(x/2)]
=tan(π/4-x/2)
=右边
命题得证