Download App

Complementary Angles — MATHEMATICS STD 9 — Question

ICSE BoardEnglish MediumSTD 9MATHEMATICSComplementary Angles2 Marks
Question
Evaluate $: \cos^2 25^\circ - \sin^2 65^\circ - \tan^2 45^\circ$
✓

Answer

$\cos^2 25^\circ - \sin^2 65^\circ - \tan^2 45^\circ$
$= [\cos(90^\circ - 65^\circ)]^2 - \sin^2 65^\circ - (\tan 45^\circ)^2$
$= \sin^2 65^\circ - \sin^2 65^\circ - (1)^2$
$= 0 - 1$
$= - 1.$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "[2 Mark Question Answer]" from Complementary Angles→Complementary Angles — all question types→MATHEMATICS STD 9 question papers→ICSE Board STD 9 question papers→ICSE Board question paper generator→

Similar questions

Factorise:
$x^3+64$
→
Expand the following$:\left(2 a+\frac{1}{2 a}\right)^2$
→
Draw the graph of:
y - x = 5
→
Factorise $: a (a - 1) - b (b - 1)$
→
Solve for x:
$\sqrt{\frac{a}{b}}=\left(\frac{b}{a}\right)^{1-3 x}$
→
Factorise:
$6(2 a+3 b)^2-8(2 a+3 b)$
→
Express the following as a single logarithm :
$2 \log _{10} 8+\log _{10} 36-\log _{10}(1.5)-3 \log _{10} 2$
→
Find the measure of each interior angle of a regular polygon of $: 6$ sides
→
Factorise by the grouping method $:ab(x^2+ 1) + x (a^2+ b^2)$
→
Without using trigonometric tables, evaluate.
$\frac{\cos 35^{\circ}}{\sin 55^{\circ}}+\frac{\sin 11^{\circ}}{\cos 79^{\circ}}-\cos 28^{\circ} \operatorname{cosec} 62^{\circ}$
→