Question 1149982
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Replace cos^2x with 1-sin^2x to obtain a quadratic equation in sinx; or replace sin^2x with 1-cos^2x to obtain a quadratic equation in cosx.<br>
Then solve the quadratic in sinx or cosx exactly the same way you would solve a quadratic in x.<br>
{{{3(cosx)^2 = 2(sinx)^2+2}}}
{{{3(cosx)^2 = 2(1-(cosx)^2)+2}}}
{{{3(cosx)^2 = 2-2*cos(x)^2+2 = 4-2*cos(x)^2}}}
{{{5(cos(x)^2) = 4}}}
{{{cos(x)^2 = 4/5}}}<br>
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