Question

Evaluate cos square 30 +sin square 45 - 1/3 tan square 60 + cos 90 .

(plz reply fast....)

Answer 1

=cos^2 30 + sin^2 45 - 1/3 tan^2 60 + cos 90
=(root 3 / 2)^2 + (1 / root 2)^2 - 1/3 (root 3)^2 + 0
=3/4+1/2-1+0
=3+2-4/4
=1/4

Answer 2

Answer:

$Value \: of \: cos^{2}30+sin^{2}45\\-\frac{1}{3}\times tan^{2}60+cos\:90\\=\frac{5}{4}$

Step-by-step explanation:

$Value \: of \: cos^{2}30+sin^{2}45\\-\frac{1}{3}\times tan^{2}60+cos\:90\\=\left(\frac{\sqrt{3}}{2}\right)^{2}+\left(\frac{1}{\sqrt{2}}\right)^{2}\\-\frac{1}{3}\times (\sqrt{3})^{2}+1\\=\frac{3}{4}+\frac{1}{2}-\frac{1}{3}\times 3+1\\=\frac{3}{4}+\frac{1}{2}-\frac{3}{3}+1\\=\frac{3}{4}+\frac{1}{2}-1+1\\=\frac{3}{4}+\frac{1}{2}\\=\frac{3+2}{4}\\=\frac{5}{4}$

Therefore,

$Value \: of \: cos^{2}30+sin^{2}45\\-\frac{1}{3}\times tan^{2}60+cos\:90\\=\frac{5}{4}$

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