Question

Match the following (Figures are rough sketches)

(i)sinx

(ii) cosx

(iii) tanx

• A. i -P, ii -Q, iii -R
• B. i -Q, ii -x, iii -P
• C. i -Q, ii -P, iii -R
• D. i -R, ii -P, iii -Q

Answer 1

The correct option is C

i -Q, ii -P, iii -R

If we plot the values of known angles for sinx, cosx, and tanx and join them we will get the respective graphs.

Let us try to plot sinx.

X = 0, sinx = 0

X = $\frac{\pi }{2}$ sin x = 1

X = $\pi$ sin x = 0

X = $\frac{3\pi }{2}$ sin x = -1

X = $2\pi$ sin x = 0

sin x is periodic with a period of $2\pi$, (sin$(2\pi +x)$ = sin x).So we will plot for the interval $[0,2\pi ]$ and replicate.

We can do the same for remaining functions. Graph of cos x and tan x will look the similar. tan x will be zero when x = 0 and infinity when x = $\frac{\pi }{2}$

Graph for cos x

Graph for tan x