If ^@\triangle ABC^@ is right angled at ^@C^@, find the value of ^@cos(A+B)^@.
Answer:
^@0^@
- We know that sum of the angles of a triangle is ^@180^\circ^@
^@\angle A + \angle B + \angle C = 180^\circ^@ - It is given that angle ^@C^@ is right angle. Replace ^@\angle C = 90^\circ^@ in above equation
^@\implies \angle A + \angle B + 90^\circ = 180^\circ^@
^@\implies \angle A + \angle B = 180^\circ - 90^\circ^@
^@\implies \angle A + \angle B = 90^\circ^@
- Now we know the value of ^@A + B^@, we can find the value of ^@cos(A+B)^@
^@\implies cos(A+B) = cos(90^\circ)^@
^@\implies cos(A+B) = 0^@