Given : $$\sqrt5tan\ \theta=5sin\ \theta$$
=> $$\frac{sin\ \theta}{cos\ \theta}=\sqrt5sin\ \theta$$
=> $$cos\ \theta=\frac{1}{\sqrt5}$$
=> $$cos^2\ \theta=\frac{1}{5}$$ ---------------(i)
Now, $$sin^2\ \theta=1-cos^2\ \theta$$
=> $$sin^2\ \theta=1-\frac{1}{5}=\frac{4}{5}$$ --------------(ii)
Subtracting equation (i) from (ii), we get :
$$\therefore$$ $$(sin^2\ \theta-cos^2\ \theta)=\frac{4}{5}-\frac{1}{5}=\frac{3}{5}$$
=> Ans - (A)
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