Question 311328
{{{f(x)=x^2+4x-2}}}
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{{{f(a)=a^2+4a-2}}}
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{{{f(a+h)=(a+h)^2+4(a+h)-2}}}
{{{f(a+h)=(a^2+2ah+h^2)+4a+4h-2}}}
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{{{f(a+h)-f(a)=(cross(a^2)+2ah+h^2)+cross(4a)+4h-cross(2)-cross(a^2)-cross(4a)+cross(2)}}}
{{{f(a+h)-f(a)=2ah+h^2+4h}}}
{{{(f(a+h)-f(a))/h=2a+h+4}}}
Then,
{{{lim(h->0,((f(a+h)-f(a))/h))=2a+4}}}