- Home
- Standard 10
- Mathematics
8. Introduction to Trigonometry
medium
$(\sec A+\tan A)(1-\sin A)=..........$
A
$\sec A$
B
$\sin A$
C
$\cos A$
D
$\operatorname{cosec} A$
Solution
$(\sec A+\tan A)(1-\sin A)$
$=\left(\frac{1}{\cos A}+\frac{\sin A}{\cos A}\right)(1-\sin A)$
$=\left(\frac{1+\sin A}{\cos A}\right)(1-\sin A)$
$=\frac{1-\sin ^{2} A}{\cos A}=\frac{\cos ^{2} A}{\cos A}$
$=\cos A$
Standard 10
Mathematics