+0

# if pi/2 < x < pi and sinx = 2/5 then tanx = ؟

+3
347
3

if pi/2 < x < pi and sinx = 2/5 then tanx = ؟

Guest Jul 27, 2014

#2
+92193
+11

I always draw the right angled triangle for these.

x is one of the acute angles

2 is the opposite side, 5 is the hypotenuse.

Get the other side using pythagoras' Theorum

then read tanx of the triangle.

plus as Alan said it is in the second quad so it is negative.

Melody  Jul 27, 2014
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#1
+26625
+8

This is in the second quadrant where tan is negative, so tanx = -2/√(52-22) = -2/√21

Alan  Jul 27, 2014
#2
+92193
+11

I always draw the right angled triangle for these.

x is one of the acute angles

2 is the opposite side, 5 is the hypotenuse.

Get the other side using pythagoras' Theorum

then read tanx of the triangle.

plus as Alan said it is in the second quad so it is negative.

Melody  Jul 27, 2014
#3
+1832
+3

thanx for all

xvxvxv  Jul 27, 2014

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