Question

The cartesian co-ordinates of a point $\left( –1,\frac{3\pi}{4} \right)$ is-

• A. $\left( \frac{1}{\sqrt{2}},\frac{1}{\sqrt{2}} \right)$
• B. $\left( \frac{–1}{\sqrt{2}},\frac{1}{\sqrt{2}} \right)$
• C. $\left( –\frac{1}{\sqrt{2}},\frac{–1}{\sqrt{2}} \right)$
• D. $\left( \frac{1}{\sqrt{2}},–\frac{1}{\sqrt{2}} \right)$

Answer 1

Answer: (D)

$\left( \frac{1}{\sqrt{2}},–\frac{1}{\sqrt{2}} \right)$

Answer 2

$\left( –1,\frac{3\pi}{4} \right)$

x = r cos q and y = r sin q

Ž x = (– 1) cos $\left( \frac{3\pi}{4} \right)$ Ž y = (– 1) sin $\left( \frac{3\pi}{4} \right)$

Ž x = (– 1) $\left( –\frac{1}{\sqrt{2}} \right)$ Ž y = (– 1) $\left( \frac{1}{\sqrt{2}} \right)$

Ž $\left( \frac{1}{\sqrt{2}},–\frac{1}{\sqrt{2}} \right)$