Question

Answer question number 21.

Answer 1

$\underline \bold {Solution:-}$

For any angle between 0° and 90° , value of cos is less than 1 but greater than 0.

We know that,

if a number less than one but greater that -1 is square , it will give the smaller number than the earlier one.

Since, value of cos¢ will be less than one between angle 0° to 90°.

So, it's square will be less than the earlier one.

Cos¢ > cos^2 ¢

so option (b) is correct.

Answer 2

21 ) Well see the attachment below !  [ see only when 0 < theta < 90 ]

Option verification:

Trial and error method

for example : cos 60 = 1/2

cos² 60 = 1/4

So  1/2 > 1/4  

==> cos θ > cos² θ

In fact this is true that cos θ > cos² θ.

Hence OPTION B seems correct .

cos θ > cos² θ

Hope it helps u :-)

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