Question

1.
Find the value of
(iv) sec 510°
(i) sin 210°
(ii) cos 315º
(iii) tan 480°​

Answer 1

Answer:

hello mate

1.sec 510°

given :

sec= 510°

sec = ( 5×90°+60°)

here n = 5 is odd , so sec changes to sec

cosec = 60°

since 510 lies in second quadrant

= √2/3

2.sin 210°

Sin 210=sin(90+120)=cos 120

Now, cos120=2cos^2 60-1=2×1/4-1=1/2-1. So cos120=-1/2

3.cos 315°

cos 315 = cos ( 360 - 45 ) = cos (2π-45)

We know cos (2π-45) = +cos 45

cos (2π-45) = cos 45 = 1/√2 (ans)

4.tan 480

Before starting remember this tan (360+x) = Tan x

So tan 480 can be broken into tan(360+120) = tan 120

Now tan 120 will fall into 2nd quadrant and therefore it will be negative

Hence tan120= tan(180–60) = - tan 60 = -√3

hope it helps