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MATHMAA

# Trigonometry-Worksheet-1

1. In triangle ABC, right angled at B, AB=24 cm, BC = 7 cm, Determine :

i. sinA, cosA

ii. sinC, cosC

Solution:

Here AB = 24 cm

BC = 7 cm

So,    AC = √($$AB^2 + BC^2$$)

AC = √625

AC = 25

i)  Sin A = $$\frac{BC}{AC}$$

Sin A  = $$\frac{7}{25}$$

Cos A = $$\frac{AB}{AC}$$

Cos A = $$\frac{24}{25}$$

ii) Sin C = $$\frac{AB}{AC}$$

Sin C = $$\frac{24}{25}$$

Cos C = $$\frac{BC}{AC}$$

Cos C = $$\frac{7}{25}$$

2.In Fig 2 find tan P - cot R.

Solution:

Here   PQ = 12 cm

PR = 13 cm

So,     QR = √($$\PR^2 - PQ^2$$)

QR = 5 cm

tan P = $$\frac{QR}{PQ}$$

= $$\frac{5}{12}$$

cot R = $$\frac{QR}{PQ}$$

= $$\frac{5}{12}$$

tan P - cot R = $$\frac{5}{12}$$ - $$\frac{5}{12}$$

= 0