Question

when, sinA+sinB =2 then what's the value of cosA+cosB ?​

Answer 1

Answer:

SinA + SinB = 2

It means A and B are 90 because sin90 = 1

sin A = 1/Cos A and Sin b = 1/cos B according to trignomatry

1/Cos A + 1/ Cos B = 2

Cos A + Cos B = 2 x Cos A Cos B

Cos A + Cos B = 2 x Cos 90 x Cos 90 = 0 Answer

Answer 2

$\displaystyle\huge\red{\underline{\underline{Solution}}}$

It is known to us that the value of Sine of an angle lies between - 1 & 1

We can write it as

For any angle $\theta$

$- 1 \leqslant sin \theta \: \leqslant 1$

Now it is given that

$sinA+sinB =2$

Which leads to

$sinA = 1 \: \: and \: \: \: sinB =1$

$\implies \: A = B = \: {90}^{ \circ}$

Hence

$cosA+cosB = \: cos {90}^{ \circ} + cos {90}^{ \circ} = 0 + 0 = 0$