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Consider a point [math](x_1,y_1)[/math] on the graph of [math]b^2x^2 + a^2y^2 = a^2b^2[/math].

• lab{3.3.9a} Find the slope of the tangent to the graph at [math](x_1,y_1)[/math].\
• Write an equation of the tangent line in \ref{ex3.3.9a}.
• Show that [math]b^2xx_1 + a^2yy_1 = a^2b^2[/math] is an equation of the tangent line.