Question

achar a soma dos numeros impares de 0 ate 50​

Answer 1

primeiro numero impar é 1

ultimo é 49

$a_1=1\\a_n=49\\r=2\\n=?\\\\\\\displaystyle \mathsf{a_n=a_1+(n-1)\times r}\\\displaystyle \mathsf{49=1+(n-1)\times2}\\\displaystyle \mathsf{49=1+2n-2}\\\displaystyle \mathsf{2n=49+1}\\\displaystyle \mathsf{2n=50}\\\displaystyle \mathsf{n=25}\\\\\\\displaystyle \mathsf{s_n=\dfrac{(a_1+a_n)\times r}{2}}\\\\\\\displaystyle \mathsf{s_{25}=\dfrac{(1+49)\times25}{2}}\\\\\\\displaystyle \mathsf{s_{25}=\dfrac{(50\times25)}{2}}\\\\\\\displaystyle \mathsf{s_{25}=\dfrac{1250}{2}\to625}$