9.If `m+2n=7`prove that `m^(3)+8n^(3)+42mn=343`

If tan A + sin A = m and tan A - sin A = n, prove that : m^(2) - n^(2) = 4 sqrt (mn)

If tantheta+sintheta=m and tantheta-sintheta=n , then prove that: m^(2)-n^(2)=4sqrt(mn)

If tantheta+sintheta=m and tantheta-sintheta=n , then prove that: m^(2)-n^(2)=4sqrt(mn)

If tanA+sinA=m and tanA-sinA=n , then prove that m^(2)-n^(2)=4sqrt(mn) .

If tanA+sinA=m and tanA-sinA=n , then prove that m^(2)-n^(2)=4sqrt(mn) .

If m and n are two distinct numbers such that m >n, then prove that m^2-n^2 ,2mn and m^2+n^2 is a Pythagorean triplet.

If m^(2)+m^(2)+2mm'cos theta=1 and n^(2)+n^(2)+2nn'cos theta=1(mn+m'n'+(mn'+m'n)cos theta=0 prove that m^(2)+n^(2)=cos ec^(2)theta

If the ratio of the roots of the quadratic equation x^(2)-px+q=0 be m:n, then prove that p^(2)mn=q(m+n)^(2) .