Practicing Success
\(\sqrt {3}\)cosec20° - sec20° =? |
sin20° 4 2 \(\frac{4sin20°}{sin40°}\) |
4 |
\(\frac{\sqrt {3}}{sin20°}\)-\(\frac{1}{cos20°}\) ⇒ \(\frac{cos20°\sqrt {3}-sin20°}{sin20°cos20°}\) Divide and multiply numerator by 2 ⇒ \(\frac{2\frac{\sqrt {3}}{2}cos20°-\frac{1}{2}sin20°}{sin20°cos20°}\) ⇒ \(\frac{2sin60°cos20°- cos60°sin20°}{sin20°cos20°}\) ⇒ Again multiply and divide the eq. by 2 2.\(\frac{2sin60°cos20°- cos60°sin20°}{2sin20°cos20°}\) [sin(A-B) = sinAcosB - cosAsinB, 2sinAcosB = sin2A] = 2.\(\frac{2sin(60°-20°)}{sin40°}\) = 4 |