# Math Help - help!

1. ## help!

If cos Θ + sin Θ = √2 cos Θ;
show that cos Θ - sin Θ = √2 sin Θ.

2. Originally Posted by snigdha
If cos Θ + sin Θ = √2 cos Θ;
show that cos Θ - sin Θ = √2 sin Θ.
Divide the first of those equations by $\cos\theta$ to see that $\tan\theta = \sqrt2-1$. Similarly, the second equation is equivalent to $\tan\theta = \frac1{\sqrt2+1}$. Now complete the argument by showing that $\sqrt2-1 = \frac1{\sqrt2+1}$,