+0

# what does x equal? 35 + sec ^2 x = 12tanx

+5
97
3

what does x equal? 35 + sec^2x = 12tanx

Guest Mar 4, 2017

#3
+7059
+5

I'm sorry about it. I need to know better about the units. Thanks for the correction, Alan!

Greeting asinus :- )

asinus  Mar 4, 2017
Sort:

#1
+7059
+10

what does x equal? 35 + sec^2x = 12tanx

$$35 + sec^2x = 12tanx$$

$$sec^2x=\frac{1}{cos^2x}=\frac{1}{\frac{1}{1+tan^2x}}=1+tan^2x$$

$$35+1+tan^2x=12tanx$$

$$tanx=z$$

$$z^2-12z+36=0$$

$$z=6\pm\sqrt{36-36}$$

$$z=6$$

$$tanx=6$$

$$x=arctan6$$

$$x=1.4056476 \ or \ x=80grd\ 32min\ 15.6sec$$

$$and \ x=1.4056476+\pi \ or \ x=80grd\ 32min\ 15.6sec+ 180grd$$

!

asinus  Mar 4, 2017
#2
+26236
+5

grd?   This suggests gradians to me!  Why not deg for degrees?

Alan  Mar 4, 2017
#3
+7059
+5

I'm sorry about it. I need to know better about the units. Thanks for the correction, Alan!

Greeting asinus :- )

asinus  Mar 4, 2017

### 8 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details